Transcutaneous analyte sensor systems and methods

ABSTRACT

Sensor systems can be used to measure an analyte concentration. Sensor systems can include a base having a distal side configured to face towards a person&#39;s skin. An adhesive can couple the base to the skin. A transcutaneous analyte measurement sensor can be coupled to the base and can be located at least partially in the host. A transmitter can be coupled to the base and can transmit analyte measurement data to a remote device.

INCORPORATION BY REFERENCE TO RELATED APPLICATION

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. This application is a continuation of U.S. application Ser.No. 15/798,064, filed Oct. 30, 2017, which claims the benefit of U.S.Provisional Application No. 62/415419, filed Oct. 31, 2016. Each of theaforementioned applications is incorporated by reference herein in itsentirety, and each is hereby expressly made a part of thisspecification.

BACKGROUND Field

Various embodiments disclosed herein relate to measuring an analyte in aperson. Certain embodiments relate to systems and methods for applying atranscutaneous analyte measurement system to a person.

Background

Diabetes mellitus is a disorder in which the pancreas cannot createsufficient insulin (Type I or insulin dependent) and/or in which insulinis not effective (Type 2 or non-insulin dependent). In the diabeticstate, the victim suffers from high blood sugar, which can cause anarray of physiological derangements associated with the deterioration ofsmall blood vessels, for example, kidney failure, skin ulcers, orbleeding into the vitreous of the eye. A hypoglycemic reaction (lowblood sugar) can be induced by an inadvertent overdose of insulin, orafter a normal dose of insulin or glucose-lowering agent accompanied byextraordinary exercise or insufficient food intake.

Conventionally, a person with diabetes carries a self-monitoring bloodglucose monitor, which typically requires uncomfortable finger prickingmethods. Due to the lack of comfort and convenience, a person withdiabetes normally only measures his or her glucose levels two to fourtimes per day. Unfortunately, such time intervals are so far spreadapart that the person with diabetes likely finds out too late of ahyperglycemic or hypoglycemic condition, sometimes incurring dangerousside effects. Glucose levels may be alternatively monitored continuouslyby a sensor system including an on-skin sensor assembly. The sensorsystem may have a wireless transmitter which transmits measurement datato a receiver which can process and display information based on themeasurements.

The process of applying the sensor to the person is important for such asystem to be effective and user friendly. The application process canresult in the sensor assembly being attached to the person in a statewhere it is capable of sensing glucose-level information, communicatingthe glucose-level information to the transmitter, and transmitting theglucose-level information to the receiver.

The analyte sensor can be placed at least partially into subcutaneoustissue. A user can actuate an applicator to insert the analyte sensorinto its functional location. This transcutaneous insertion can lead toincomplete sensor insertion, improper sensor insertion, exposed needles,and/or unnecessary pain. Thus, in some cases it can be advantageous forsystems that more reliably enable transcutaneous sensor insertion andremoval while being easy to use and relatively pain-free.

SUMMARY

Various systems and methods described herein enable reliable, simple,and pain-minimizing transcutaneous insertion of analyte sensors. Someembodiments comprise an on-skin sensor assembly. Some embodimentscomprise a system for applying an on-skin sensor assembly to a person'sskin. The sensor can be an analyte sensor, a glucose sensor, any sensordescribed herein and/or incorporated by reference, and/or any othersuitable sensor.

In some embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), a sensor systemfor measuring an analyte concentration comprises a base having a distalside configured to face towards a skin of a host; a first adhesivecoupled to the base and configured to couple the base to the skin; atransmitter coupled to the base and configured to transmit analytemeasurement data; a transcutaneous analyte measurement sensor coupled tothe base; and a collapsible support member configured to resistnon-axial forces of the sensor, the collapsible support member comprisesa channel, and a portion of the sensor passes through the channel,wherein the channel is configured to resist a buckling force of thesensor as the sensor moves from the proximal position to the distalposition.

In some embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), a sensor systemfor measuring an analyte concentration comprises a base having a distalside configured to face towards a skin of a host; a first adhesivecoupled to the base and configured to couple the base to the skin; atransmitter coupled to the base and configured to transmit analytemeasurement data; a transcutaneous analyte measurement sensor coupled tothe base; and wherein the sensor is configured to be bent against thefirst adhesive or the base after removal of the base from the skin.

In some embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), a sensor systemfor measuring an analyte concentration comprises a base having a distalside configured to face towards a skin of a host; a first adhesivecoupled to the base and configured to couple the base to the skin; atransmitter coupled to the base and configured to transmit analytemeasurement data; and/or a transcutaneous analyte measurement sensorcoupled to the base.

In several embodiments (i.e., optional and independently combinable withany of the aspects and embodiments identified herein), the base isconfigured to retract a distal tip of the sensor into an interior areaof the base. The system can comprise a spring (e.g., a helical spring, aconical spring, a compression spring, a tension spring, a leaf spring, atorsion spring) configured to retract the distal tip of the sensor intothe interior area of the base.

In some embodiments, the system is configured to cover the distal tip ofthe sensor (e.g., after the sensor has been removed from the tissue).

In several embodiments, the system comprises a latch. The latch cancomprise a locked state in which the latch couples the transmitter tothe base. The latch can also comprise an unlocked state configured toenable removing the transmitter from the base.

In some embodiments, the sensor system is configured to retract at leasta portion of the sensor into a receptacle in response to removing thesensor system from the skin. The sensor can comprise a retractabledistal tip. The base can comprise an interior area configured to receivethe distal tip in response to a retraction of the distal tip. The systemcan comprise a spring configured to retract the distal tip. The springcan be coupled to the base.

In several embodiments, the system comprises a first adhesive configuredto couple the base to the skin. The system can comprise a secondadhesive configured to bend and/or deflect a portion of the sensoragainst the base.

In some embodiments, the sensor comprises a section located distallyrelative to the base. The section can comprise a first portion and asecond portion. The first portion of the sensor can be configured tofacilitate maintaining the second portion in a straight configurationduring insertion of the section into the skin. The first portion of thesensor can be configured to soften in response to being located in vivo.

In several embodiments, the first portion comprises a first bucklingresistance prior to the insertion and a second buckling resistance after12 hours to 48 hours of being located in vivo. The second bucklingresistance can be less than the first buckling resistance. The secondbuckling resistance can be at least 30 percent less and/or at least 70percent less than the first buckling resistance.

In some embodiments, the system comprises a pull tab system thatincludes a pull tab. The pull tab system can be configured to retractthe sensor in response to moving the pull tab relative to the base.

In several embodiments, the pull tab system comprises a channel and anintermediate portion that couples the channel to the pull tab. The pulltab can protrude away from the base. A first portion of the sensor canpass through the channel. The pull tab system can be configured suchthat pulling the pull tab moves the channel to retract the sensor.

In some embodiments, the channel is formed by a hole, a slot, a hoop, ahook, a valley, and/or any suitable structure. The channel can be formedby a wall configured to push and/or pull the sensor. The channel can beopen on one side to facilitate assembling the system (by enabling thesensor to be inserted into the channel through the open side).

In several embodiments, the base can comprise a second hole. A secondportion of the sensor can pass through the second hole. The pull tabsystem can be configured such that pulling the pull tab retracts thesensor by pulling the second portion of the sensor out of the secondhole and into an interior area of the sensor system.

In some embodiments, the pull tab system is slidably coupled to the basesuch that the pull tab system is configured to slide in a firstdirection that is within 20 degrees (e.g., within plus or minus 20degrees) and/or within 45 degrees (e.g., within plus or minus 45degrees) of being perpendicular to a proximal direction oriented awayfrom the skin. (The pull tab system can be configured to slide in adirection that is within plus or minus 20 degrees and/or within plus orminus 45 degrees of being perpendicular to a distal direction orientedtowards the skin.)

In several embodiments, the transmitter is slidably coupled to the basesuch that the transmitter is configured to slide in a second directionthat is within plus or minus 20 degrees and/or within plus or minus 45degrees of being perpendicular to the proximal direction. The seconddirection can be within plus or minus 20 degrees and/or within plus orminus 45 degrees of being parallel to the first direction.

In some embodiments, the system comprises a push button system having apush button. The push button system can be configured to retract thesensor in response to pushing the button. At least a portion of the pushbutton system can protrude away from the base. The push button systemcan be configured such that pressing the portion of the push buttonsystem into the base engages a sensor retraction hoop or hook that pullsand/or pushes the sensor into an interior area of the sensor system.

In several embodiments, the push button system comprises a channel andan intermediate portion that couples the channel to the push button. Thepush button can protrude away from the base. A first portion of thesensor can pass through the channel. The push button system can beconfigured such that pushing the button moves the channel to retract thesensor.

In some embodiments, the channel is formed by a hole, a slot, and/or ahook. The channel can be formed by a wall configured to push and/or pullthe sensor. The channel can be open on one side to facilitate assemblingthe system (by enabling the sensor to be inserted into the channelthrough the open side).

In several embodiments, the base comprises a second hole. A secondportion of the sensor can pass through the second hole. The push buttonsystem can be configured such that pushing the button retracts thesensor by pulling the second portion of the sensor out of the secondhole and into an interior area of the sensor system by making a thirdportion of the sensor form a U-shape.

In some embodiments, the push button system is slidably coupled to thebase such that the push button system is configured to slide in a firstdirection that is within plus or minus 20 degrees and/or within plus orminus 45 degrees of being perpendicular to a proximal direction orientedaway from the distal side of the base.

In several embodiments, the transmitter is slidably coupled to the basesuch that the transmitter is configured to slide in a second directionthat is within plus or minus 20 degrees and/or within plus or minus 45degrees of being perpendicular to the proximal direction. The seconddirection can be within plus or minus 20 degrees and/or within plus orminus 45 degrees of being parallel to the first direction.

In some embodiments, the system comprises a spring-loaded arm slidablycoupled to the base such that removing the sensor system from the skincauses the sensor to automatically retract in response to the armsliding relative to the base. The base can be configured to face towardsthe skin in a first direction. The arm can be configured to slide in asecond direction that is within plus or minus 20 degrees and/or withinplus or minus 45 degrees of perpendicular to the first direction. Atleast a portion of the sensor can pass through a portion of the arm suchthat moving the arm in the second direction causes the portion of thearm to retract the sensor into an interior area (e.g., a cavity) of thesensor system.

In several embodiments, the system comprises an independent orintegrally molded spring and a releasable interlocking feature (such asa pin). The spring can be in at least one of a compressed state and anextended state (e.g., a stretched state) such that moving theinterlocking feature (e.g., removing the release pin) causes the springto move at least a first portion of the sensor into the base.

In some embodiments, the system comprises an arm slidably coupled to thebase. The arm can comprise a first channel (e.g., formed by a hole, aslot, hoop, and/or a hook). The first channel can be aligned with asecond hole of the base such that a second portion of the sensor passesthrough the first channel and the second hole. The spring can be atleast one of compressed and extended (e.g., stretched) between a firstwall of the base and a second wall of the arm. The interlocking feature(e.g., the release pin) can pass through a third hole of the base andcan interfere with a portion of the arm to prevent the spring frommoving the arm to retract the sensor.

In several embodiments, the interlocking feature (e.g., the release pin)comprises a distal face having a second adhesive configured to beapplied to the skin such that removing the base from the skin uncouplesthe first adhesive from the skin but does not uncouple the secondadhesive from the skin, which causes the interlocking feature (e.g., therelease pin) to be removed from the third hole, and thereby enables thespring to move the arm to retract the sensor. The first adhesive and thesecond adhesive can be two independent adhesive members or can be partsof one adhesive. The first and second adhesives can be coupled by acompliant adhesive backing member.

In some embodiments, the system comprises a spring-loaded arm slidablycoupled to the base and configured such that removing the sensor systemfrom the skin causes the arm to contact a first portion of the sensorand bend the sensor such that a second portion of the sensor is locatedbetween the arm and the base.

In several embodiments, the base is configured to face towards the skinin a first direction. The sensor system can comprise a spring orientedwithin plus or minus 20 degrees and/or within plus or minus 45 degreesof perpendicular to the first direction. The spring can be located in aninterior area of the sensor system and can be configured to cause thearm to collide with the first portion of the sensor.

In some embodiments, the base is configured to face towards the skin ina first direction. The arm can be configured to slide in a seconddirection that is within plus or minus 20 degrees of perpendicular tothe first direction such that the second portion of the sensor isoriented within plus or minus 20 degrees of perpendicular to the firstdirection.

In several embodiments, the sensor passes through a hole of the base.The first portion of the sensor can be located distally relative to thehole of the base. The arm can be spring-loaded towards the first portionof the sensor. The arm can comprise a protrusion that protrudes towardsthe first portion of the sensor such that sliding the arm causes theprotrusion to collide with the first portion of the sensor and positionsthe protrusion directly distally relative to the hole of the base.

In some embodiments, the protrusion of the arm comprises a secondadhesive configured to couple the arm to the skin such that the secondadhesive holds the arm in a first position in which the arm does notbend the sensor. Uncoupling the second adhesive from the skin can causethe arm to the bend the sensor such that the second portion of thesensor is located between the arm and the base.

In several embodiments, the system comprises an arm rotatably coupled tothe base by a hinge. The hinge can be configured such that uncouplingthe base from the skin causes the hinge to rotate such that the armbends at least a first portion of the sensor and covers at least asecond portion of the sensor. The system can comprise a spring (e.g., atorsional spring) coupled to the arm such that the spring biases the armin a rotational direction towards the second portion of the sensor.

In some embodiments, the hinge is located in an interior area of thesensor system. The arm can comprise a portion configured to cover thesecond portion of the sensor. The sensor system can comprise a firststate in which the portion of the arm is located in the interior areaand a second state in which the portion of the arm is located distallyrelative to the base.

In several embodiments, the sensor system comprises a first portion anda second portion. The second portion can be coupled to the first portionby a hinge configured such that increasing or decreasing a pivot anglebetween the first portion and the second portion retracts the sensor.

In some embodiments, the system comprises a spring (e.g., a helicalspring, a compression spring, a tension spring, a leaf spring, atorsional spring). The spring can be configured to increase or decreasethe pivot angle (e.g., once released by a triggering mechanism and/orany suitable mechanism).

In several embodiments, the hinge comprises a pin rotatably coupled to asleeve configured to retain the pin as the second portion rotatesrelative to the first portion.

In some embodiments, the base comprises the first portion and the secondportion. The first portion can couple the first adhesive to the secondportion.

In several embodiments, the base comprises the first portion. The secondportion can comprise the transmitter.

In some embodiments, a distal portion of the sensor passes through ahole of the base. A proximal portion of the sensor can be coupled to thesecond portion such that increasing or decreasing the pivot angleretracts the distal portion of the sensor through the hole of the baseand into an area between the first and second portions of the sensorsystem.

In several embodiments, the base comprises a left half and a right half.The left half can comprise the hole of the base. The right half cancomprise at least a portion of the hinge.

In some embodiments, the second portion comprises a lift tab configuredto enable a user to grip a distally facing surface to rotate the secondportion relative to the first portion. The lift tab can comprise aprotrusion that protrudes away from the hinge.

In several embodiments, the base comprises a first portion and a secondportion. The second portion of the base can be coupled to the firstportion of the base by a hinge configured such that decreasing a pivotangle between the first and second portions of the base places a portionof the sensor between the first and second portions of the base. Thehinge can comprise a first pin rotatably coupled to a first holeconfigured to retain the first pin as the first portion of the baserotates relative to the second portion of the base. The hinge cancomprise a second pin rotatably coupled to a second hole configured toretain the second pin as the first portion of the base rotates relativeto the second portion of the base. The first pin can protrude in a firstdirection. The second pin can protrude in a second direction that isopposite relative to the first direction.

In some embodiments, the first adhesive comprises a first section and asecond section. The first section can be coupled to the first portion ofthe base such that the first section is configured to adhere the firstportion of the base to the skin. The second section can be coupled tothe second portion of the base such that the second section isconfigured to adhere the second portion of the base to the skin. Thehinge can be configured to enable the first section of the firstadhesive to face towards the second section of the first adhesive whilethe portion of the sensor is at least partially confined between thefirst and second portions of the base.

In several embodiments, the system is configured to bend and/or deflectthe portion of the sensor in response to rotating the hinge. The portionof the sensor can be bent between the first and second portions of thebase to guard against a distal tip of the sensor penetrating tissueafter the sensor system is removed from the skin.

In some embodiments, the first portion of the base is rotationallyspring-loaded relative to the second portion of the base such that thesystem is configured to decrease the pivot angle in response to arotational spring bias. The system can comprise a torsional springcoupled to the hinge such that the torsional spring is configured todecrease the pivot angle to place the portion of the sensor between thefirst and second portions of the base.

In some embodiments, the system comprises an adhesive portion configuredto bend at least a portion of the sensor towards the base. A distal tipof the sensor can be located between the base and the adhesive portion.The system can comprise an adhesive portion configured to collapse atleast a portion of the sensor against the base.

In several embodiments, the system comprises a pliable sheet that coversa distal tip of the sensor and adheres to the first adhesive such thatthe pliable sheet guards against the distal tip of the sensorpenetrating tissue after the sensor system is removed from the skin.

In some embodiments, the first adhesive couples the pliable sheet to thebase. The pliable sheet can comprise a first state in which the pliablesheet is folded, is located proximally relative to the distal tip, doesnot cover the distal tip, and forms a tab configured to enable a user tounfold the pliable sheet.

In several embodiments, the pliable sheet comprises a second state inwhich the pliable sheet is at least partially unfolded relative to thefirst state, is at least partially located distally relative to thedistal tip, and the distal tip of the sensor is at least partiallyconfined between the pliable sheet and the first adhesive.

In some embodiments, the system comprises a second sheet having a secondpuncture resistance that is greater than a first puncture resistance ofthe pliable sheet. The second sheet can be located between the distaltip and the pliable sheet to protect the pliable sheet from beingpunctured by the distal tip. The second sheet can be coupled to thepliable sheet such that the second sheet deforms the distal tip as thepliable sheet is folded over the distal tip.

In some embodiments, a distal tip of the sensor is at least partiallyconfined between a pliable sheet and the base such that the pliablesheet holds at least a portion of the sensor in a bent position and thepliable sheet is adhered to the first adhesive.

In some embodiments, the pliable sheet comprises a first state and asecond state. In the first state, the pliable sheet can be locatedproximally relative to the first adhesive when the sensor system iscoupled to the skin. In the second state, the pliable sheet can belocated distally relative to the first adhesive when the distal tip ofthe sensor is at least partially confined between the pliable sheet andthe base.

In several embodiments, a distal side of the base comprises a slotconfigured to receive a distal end of the sensor after the sensor isremoved from the host. A first portion of the sensor can be bent and/ordeflected such that the distal end of the sensor is located in the slot.Once the sensor is bent, the distal end of the sensor can be locatedproximally relative to the first adhesive.

In several embodiments, the base comprises a channel (e.g., a hole). Asecond portion of the sensor can pass through the hole. The slot can bedirectly coupled to the hole (e.g., such that the hole and the slot arein fluid communication). The slot can be oriented within plus or minustwenty degrees of perpendicular a central axis of the hole.

In some embodiments, the sensor system comprises a first portion and asecond portion. The first portion can couple the first adhesive to thesecond portion. The second portion can be rotatably coupled to the firstportion about an axis of rotation that is within plus or minus twentydegrees of being parallel to a proximal direction such that the sensorsystem is configured to retract the sensor in response to rotating thesecond portion relative to the first portion. The base can comprise thefirst portion. The second portion can comprise the transmitter.

In several embodiments, the system comprises an interior area betweenthe first portion and the second portion. The interior area can beconfigured such that spinning the second portion relative to the firstportion moves the interior area relative to at least one of the firstportion and the second portion. The interior area can be configured suchthat spinning the second portion relative to the first portion retractsat least a portion of the sensor through a hole in the base and into theinterior area.

In some embodiments, the base comprises a distally facing hole. Thesensor can comprise a proximal portion coupled to the second portion anda distal portion that passes through the hole in the base.

In several embodiments, the system comprises a proximally facingindentation configured to provide traction for a user to rotate thesecond portion relative to the first portion. The system can comprise aproximal protrusion configured to provide traction for a user to rotatethe second portion relative to the first portion.

In some embodiments, the system comprises an extendable cover having afirst state configured to enable a distal end of the sensor to enter thehost and having a second state configured to cover the distal end of thesensor after the sensor is removed from the host. The first state can bea contracted state. The second state can be an extended state.

In several embodiments, the cover is a pliable sheath having a channelin which a portion of the sensor is located. The cover can be rolled upalong the channel.

In some embodiments, the extended state is a relaxed state such that thecover is configured to unroll from the retracted state in response tothe sensor system being removed from the host.

In several embodiments, the retracted state has a higher storedmechanical energy than the extended state such that the cover isconfigured to unroll from the retracted state in response to the sensorsystem being removed from the host.

In some embodiments, the cover comprises bellows (e.g., a pleatedexpandable portion) configured to at least partially unfold to enablethe cover to move from the retracted state to the extended state. Thepleated expandable portion can comprise a channel in which a firstportion of the sensor is located. The expandable portion can comprise apleated collapsible portion. The cover can comprise a distal holethrough which a second portion of the sensor passes in the retractedstate.

In several embodiments, the retracted state has a higher storedmechanical energy than the extended state such that the pleatedexpandable portion is configured to expand from the retracted state inresponse to the sensor system being removed from the host.

In some embodiments, the system comprises a cap that covers a distal endof the sensor such that the cap is configured to prevent the distal endfrom penetrating a person after the sensor system is removed from thehost and the cap is coupled to the distal side of the base.

In several embodiments, the cap comprises a channel and/or a cavityhaving a first central axis. The base can comprise a hole having asecond central axis. A portion of the sensor can pass through the holeand into a channel. The first central axis can be within twenty degreesof parallel to the second central axis. The first central axis of thechannel can pass through the hole of the base (e.g., as the firstcentral axis extends beyond a proximal end of the channel).

In some embodiments, the system comprises a cap coupled to the base. Thecap can cover at least a majority of the first adhesive. The cap cancover a distal end of the sensor such that the cap is configured toprevent the distal end from penetrating a person after the sensor systemis removed from the host and the cap is coupled to the base. The cap cancomprise sidewalls that protrude proximally past at least a portion ofan outer perimeter of the sensor system (and/or past at least a portionof an outer perimeter of the base).

In several embodiments, the system comprises a sensor cover having aninterior area and a protrusion. At least a portion of the base can belocated in the interior area of the sensor cover such that a distal endof the sensor is located between the base and the sensor cover. Theprotrusion can be located in a hole of the base such that the protrusionunlatches the transmitter from the base.

In some embodiments, the system comprises a sensor cover configured tounlock the transmitter from the base in response to coupling the base tothe sensor cover. The sensor cover can be configured to enableuncoupling the transmitter from the base in response to coupling thebase to the sensor cover (e.g., by unlatching the transmitter from thebase). The transmitter can be configured to be uncoupled from the baseonce the transmitter is unlocked from the base.

In several embodiments, the system comprises a first flex arm and awall. The first flex arm can comprise a first state in which the firstflex arm interferes with the wall to lock the transmitter to the base.

In some embodiments, the sensor cover comprises a protrusion configuredsuch that coupling the base to the sensor cover causes the protrusion tomove the first flex arm to a second state in which the first flex armdoes not interfere with the wall such that the first flex arm does notlock the transmitter to the base.

In several embodiments, the base comprises a hole through which at leasta portion of the protrusion passes to deflect the first flex arm to thesecond state.

In several embodiments, the sensor cover comprises a housing and asecond flex arm. The housing can comprise an interior area. At least aportion of the base can be located inside the interior area of thehousing. The second flex arm can couple the protrusion to the housingsuch that the second flex arm is configured to bend to move theprotrusion to facilitate inserting the portion of the base into theinterior area of the housing.

In some embodiments, the second flex arm is configured to move in adistal direction in response to coupling the base to the sensor cover.The first flex arm can be configured to move in a proximal direction inresponse to coupling the base to the sensor cover. A portion of thesensor can be bent in response to coupling the base to the sensor coversuch that a distal end of the sensor is located between the base and thesensor cover.

In several embodiments, the sensor cover comprises a first side and asecond side. The first side can be oriented within plus or minus thirtydegrees of perpendicular to the second side. The first side can comprisea first hole through which the portion of the base is inserted. Thesecond side can comprise a second hole configured to provide access to aproximal surface of the transmitter to facilitate removing thetransmitter from the base.

In some embodiments, the system comprises a rail. The rail can slidablycouple the base to the transmitter.

In several embodiments, the system comprises a sensor cover configuredto unlatch the transmitter from the base in response to coupling thebase to the sensor cover. The system can comprise a first flex armconfigured to latch the base to the transmitter. The sensor cover cancomprise a second flex arm configured to deflect the first flex arm tounlatch the transmitter from the base.

In some embodiments, the sensor cover comprises a distally facing wall.At least a portion coupled to the base (e.g., a proximal side of thebase) can be pressed against the distally facing wall such that aprotrusion of the second flex arm is pressed into a hole of the base todeflect the first flex arm.

In several embodiments, the system comprises a telescoping assemblycoupled to the base. At least a first portion of the sensor can belocated between a portion of the telescoping assembly and a distal sideof the base such that the telescoping assembly is configured to movefrom a distal position to a proximal position to retract a secondportion of the sensor into a protective cavity of the system.

In some embodiments, the base comprises an interior channel having aproximally facing opening. The telescoping assembly can be located atleast partially in the interior channel such that the telescopingassembly is configured to move proximally at least partially in theinterior channel from the distal position to the proximal position.

In several embodiments, when the telescoping assembly is in the distalposition, the first portion of the sensor can be located in the interiorchannel of the base, and the second portion of the sensor can be locateddistally relative to the base. When the telescoping assembly is in theproximal position, the first and second portions of the sensor can belocated in the interior channel of the base.

In some embodiments, the telescoping assembly comprises a first sectionand a second section. The first section can be slidably coupled to thesecond section. The second section can be slidably coupled to aninterior channel of the base such that the telescoping assembly isconfigured to telescope relative to the base to retract the sensor.

In several embodiments, the interior channel comprises a first overhang(which can be oriented radially inward). The first overhang can beconfigured to interfere with a second overhang (which can be orientedradially outward) of the second section to retain at least a portion ofthe second section within the interior channel.

In some embodiments, the second section comprises a third overhang(which can be oriented radially inward). The third overhang can beconfigured to interfere with a fourth overhang (which can be orientedradially outward) of the first section to limit a distance the firstsection can move proximally relative to the second section.

In several embodiments, the system comprises a spring and a lockingmechanism. The locking mechanism can be configured to lock thetelescoping assembly in the distal position. The locking mechanism cancomprise a first overhang of the base and a second overhang of the firstsection. The first and second overhangs can be configured such that in afirst angular position of the first section relative to the base, thefirst overhang interferes with the second overhang to limit proximaltravel of the first section relative to the base. In some embodiments,in a second angular position of the first section relative to the base,the first overhang does not limit the proximal travel of the firstsection relative to the base such that the spring pushes the telescopingassembly to the proximal position.

In some embodiments, the base comprises a first overhang configured tolimit a first proximal travel of the second section relative to thebase. The base can comprise a second overhang configured to impedeproximal movement of the first section such that the telescopingassembly is held in the distal position.

In several embodiments, the base comprises a first channel. The secondsection can comprise a radially outward protrusion located in the firstchannel such that the first channel limits a first angular movement ofthe second section relative to the base, while the second sectionpermits a second angular movement of the first section relative to thesecond section and relative to the base.

In some embodiments, the sensor comprises a deformable connection thatcommunicatively couples (and/or electrically couples) a subcutaneousportion of the sensor to a connection portion of the sensor. Theconnection portion of the sensor can be located inside the base and cancommunicatively couple the subcutaneous portion of the sensor to acommunication module of the sensor system.

In several embodiments, in the proximal position, the subcutaneousportion of the sensor can be located within a center region of a coil(e.g., a deformable connection) of the sensor. In many embodiments, thedeformable connection is configured such that the subcutaneous portionof the sensor is not located in a center region of the deformableconnection.

In some embodiments, the deformable connection of the sensor does notapply a biasing force. In several embodiments, the coil of the sensorcan apply a biasing force to push the telescoping assembly to theproximal position. In many embodiments, a spring applies a biasingforce.

In several embodiments, the system comprises a housing slidably coupledto the base. The housing can move proximally relative to the base toretract the sensor.

In some embodiments, at least a first portion of the sensor is locatedbetween a portion of the housing and a distal side of the base such thatthe housing is configured to move from a distal position to a proximalposition to retract a second portion of the sensor.

In several embodiments, the base comprises an interior channel having aproximally facing opening. The housing can be located at least partiallyin the interior channel such that the housing is configured to moveproximally at least partially in the interior channel from the distalposition to the proximal position to retract the second portion of thesensor into the interior channel.

In some embodiments, the system comprises a cap coupled to the base andlocated proximally relative to the base. A first portion of the sensorcan be coupled to the cap. The system can be configured such that movingthe cap proximally relative to the base retracts the sensor.

In several embodiments, the cap is movable between a distal position anda proximal position. In the distal position, a second portion of thesensor can be located distally relative to the base. In the proximalposition, the second portion of the sensor can be located proximallyrelative to the base. An interlock can removably secure the cap in thedistal position.

In some embodiments, at least a portion of an outer perimeter of the capprotrudes farther radially outward (relative to a central axis of thesecond portion) than the base such that the outer portion of the outerperimeter provides a distally facing wall to enable a user to grip thecap as the user moves the cap from the distal position to the proximalposition.

In several embodiments, the system comprises a linkage between the capand the base. The linkage can be configured to limit a distance that thecap can move proximally relative to the base.

In some embodiments, the linkage comprises a pleated expandable portionthat is collapsible and is configured to at least partially unfold toenable the cap to move from the distal position to the proximal positionto retract the second portion of the sensor into the pleated expandableportion. The cap can be rigidly coupled to the transmitter such thatmoving the transmitter retracts the sensor proximally.

In several embodiments, a sensor system is configured to measure ananalyte indication. A sensor system can comprise a base having a distalside configured to face towards a skin of a host; a first adhesivecoupled to the base and configured to couple the base to the skin; atransmitter coupled to the base and configured to transmit analytemeasurement data; and/or a transcutaneous analyte measurement sensorcoupled to the base.

In some embodiments, the system comprises a collapsible support memberconfigured to resist non-axial forces of the sensor. The collapsiblesupport member can comprise a proximal end, a distal end, and a lengthmeasured from the proximal end to the distal end. The system can beconfigured to reduce the length in response to moving the sensor from aproximal position to a distal position.

In several embodiments, a collapsible support member comprises achannel. At least a portion of the sensor can pass through the channel.The channel can be configured to resist a buckling force of the sensoras the sensor moves from the proximal position to the distal position.

In some embodiments, the collapsible support member comprises a foamblock having a channel. At least a portion of the sensor can passthrough the channel.

In several embodiments, the collapsible support member comprises bellowshaving a channel. A portion of the sensor passes through the channel.

In some embodiments, the system comprises a tab coupled to thecollapsible support member. The system can be configured such thatactuating (e.g., pulling, pushing, moving, pressing) the tab causes thecollapsible support member to collapse and causes at least a portion ofthe sensor to move distally relative to the base.

In several embodiments, the system comprises a foam portion (e.g., afoam block) coupled to the base and a channel mechanically supported bythe foam portion. At least a portion of the sensor can be located in thechannel. The portion of the sensor can comprise a central axis. Thechannel can be configured to resist lateral displacement of the portionof the sensor relative to the central axis. The foam portion can beconfigured to compress in response to the system moving the sensor froma proximal position (e.g., a proximal starting position) to a distalposition (e.g., a distal ending position).

In some embodiments, the base comprises a distal portion and a proximalportion. The system can comprise a channel having walls configured tocompress in response to the system moving the sensor from a proximalposition to a distal position. The channel can be located at leastpartially between the distal portion and the proximal portion of thebase such that a portion of the sensor is located in the channel. Thewalls of the channel can be configured to resist lateral displacement ofthe portion of the sensor.

In several embodiments, the walls comprise foam configured to compressin response to moving the proximal portion distally towards the distalportion of the base. The walls can be made from collapsible structuresand/or compressible materials other than foam.

In some embodiments, the walls comprise a proximal section having afirst material, an intermediate section having a second material, and adistal section having a third material. The second material can be morerigid than the first and third materials such that the intermediatesection is configured to resist the lateral displacement. The secondmaterial can be stiffer than the first and third materials such that theintermediate section is configured to resist the lateral displacement.The second material can be less compressible than the first and thirdmaterials.

In several embodiments, the system comprises an interlock (e.g., amechanical interlock) configured to secure the proximal portion of thebase to the distal portion of the base in response to the system movingthe sensor from the proximal position to the distal position.

In some embodiments, the system comprises bellows coupled to the base.At least a portion of the sensor can be located in an interior area ofthe bellows. The portion of the sensor can comprise a central axis. Thebellows can be configured to resist lateral displacement of the portionrelative to the central axis. The bellows can be configured to compressin response to the system moving the sensor from a proximal position toa distal position.

In several embodiments, the system comprises an interlock coupled to thebase and configured to secure the bellows in a compressed state. Theinterlock can be a snap fit formed by an undercut.

In some embodiments, the system comprises a distal portion of the baseand a proximal portion. The bellows can couple the distal portion to theproximal portion. The system can comprise a removable interferencemember (e.g., a safety member) located between the distal portion andthe proximal portion such that the removable interference member isconfigured to block the system from moving the sensor from the proximalposition (e.g., a proximal starting position) to the distal position(e.g., a distal ending position).

In several embodiments, the system comprises a pull tab and a slotconfigured such that at least a portion of the sensor is located in theslot. The system can be configured such that pulling the pull tab causesthe system to move the sensor from a proximal position to a distalposition

In some embodiments, the system comprises a compliant sheet located inthe slot and coupled to the pull tab such that the compliant sheet isconfigured to move (e.g., push, pull) the portion of the sensor distallyin response to actuating (e.g., pulling) the pull tab.

In several embodiments, the system comprises a housing coupled to thebase. The housing can comprise the slot and can be configured to causethe compliant sheet to push the portion of the sensor distally inresponse to pulling the pull tab. The slot can comprise a distallyfacing opening configured to allow the portion of the sensor to exit theslot distally and enter subcutaneous tissue of the host.

In some embodiments, a system comprises a guide member configured toresist non-axial forces of the sensor. The guide member can comprise anengagement feature releasably coupled to the sensor. The engagementfeature can be configured to uncouple from the sensor in response tomoving the sensor from a proximal position to a distal position.

In several embodiments, a guide member comprises a first portion and asecond portion. At least a portion of the sensor can be located betweenthe first and second portions of the guide member such that the firstand second portions of the guide member are configured to resist abuckling force of the sensor.

In some embodiments, the first portion can be configured to moverelative to the second portion of the guide member in response to thesystem moving the sensor from a proximal position to a distal position.The guide member can be configured such that displacement of the firstportion relative to the second portion permits moving the sensor fromthe proximal position to the distal position.

In several embodiments, the portion of the sensor (that is locatedbetween the first and second portions of the guide member) comprises acentral axis. The first and second portions of the guide member can forma channel. The portion of the sensor can be located in the channel. Thechannel can be configured to resist displacement of the portion of thesensor in a direction perpendicular to the central axis.

In some embodiments, the system comprises a channel having a first sideand a second side configured to at least partially separate in responseto the system moving the sensor from a proximal position to a distalposition. A portion of the sensor can be located in the channel suchthat the channel is configured to at least partially separate to permitthe sensor to move from the proximal position to the distal position.The portion of the sensor can comprise a central axis. The channel canbe configured to resist displacement of the portion of the sensor in adirection perpendicular to the central axis.

In several embodiments, a sensor is coupled to a housing that isslidably coupled to the base. The system can be configured to move aportion of the sensor away from the distal side of the base in responseto moving the housing in a first direction within plus or minus 20degrees and/or within plus or minus 45 degrees of perpendicular to adistal direction.

In some embodiments, the system comprises a housing slidably coupled tothe base. The base can comprise a curved channel and/or a channeloriented at an angle within plus or minus 45 degrees of parallel to adistal direction. A portion of the sensor can be located in the channel.The channel can be configured to deflect the portion of the sensor toredirect the portion distally in response to moving the housing relativeto the base.

In several embodiments, a sensor path has a first section and a secondsection. The first section can be oriented within plus or minus 20degrees of perpendicular to a distal direction and/or within plus orminus 45 degrees of perpendicular to a distal direction. The secondsection can be oriented within plus or minus 45 degrees of parallel tothe distal direction. The system can be configured to deflect the sensorto cause the sensor to follow the sensor path such that the channelredirects the sensor towards the skin of the host.

In some embodiments, the base comprises a first portion and a secondportion. The first portion can be configured to couple the secondportion to the skin. The second portion can be slidably coupled to thefirst portion. The base can be configured such that moving the secondportion in a first direction within plus or minus 20 degrees ofperpendicular to a distal direction (and/or within plus or minus 45degrees of perpendicular to a distal direction) causes a distal tip ofthe sensor to move in a second direction within plus or minus 45 degreesof parallel to the distal direction.

In several embodiments, the sensor comprises a distal section and aproximal section. The proximal section can be rigidly coupled to thesecond portion of the base. The distal section can pass through achannel of the first portion of the base. The channel can comprise aradius configured to deflect at least a portion of the sensor such thatthe portion of the sensor is redirected distally towards the skin of thehost.

In some embodiments, the sensor is a glucose sensor and/or any type ofsensor described herein and/or incorporated by reference. Thetransmitter can be coupled to the second portion of the base such thatthe second portion slidably couples the transmitter to the first portionof the base. The system can comprise at least one rail that slidablycouples the second portion to the first portion of the base.

In several embodiments, the system comprises a removable applicatorcoupled to the base. The applicator can be any type of applicatordescribed herein and/or incorporated by reference.

In some embodiments, the applicator comprises a curved channelconfigured to guide a portion of the sensor along a curved path as theportion of the sensor moves from a proximal position to a distalposition. The applicator can comprise a leaf spring configured to drivethe portion of the sensor along the curved path through the curvedchannel.

In several embodiments, a curved channel is coupled to the base. Acurved portion of the sensor can be located in the curved channel. Thecurved channel can be configured to resist buckling forces of the curvedportion as the system moves the curved portion from a proximal positionto a distal position. The applicator can be configured to facilitatemoving the curved portion from the proximal position to the distalposition.

In some embodiments, the system comprises a spring configured to movethe curved portion from the proximal position to the distal position.The spring can be any type of spring described herein and/orincorporated by reference. The spring can be a leaf spring in a flexedstate.

In several embodiments, the system comprises an interlock (e.g., amechanical interlock) configured to releasably hold the spring (e.g., aleaf spring) in a flexed state. The system can be configured to move thecurved portion from the proximal position to the distal position inresponse to releasing the interlock. The system can comprise a tab(e.g., a pull tab) coupled to the interlock such the system isconfigured to disengage the interlock to enable the spring to move thecurved portion from the proximal position to the distal position inresponse to actuating (e.g., pulling) the tab.

In some embodiments, the system comprises a first arm and a wall coupledto the base. A portion of the sensor can be secured between the firstarm and the wall such that the first arm is configured to resistbuckling forces of the sensor as the system moves the portion of thesensor from a proximal position to a distal position.

In several embodiments, the first arm is movably coupled to the basesuch that at least a portion of the first arm is configured to move(e.g., relative to the base, relative to an applicator housing) toenable the system to move the portion of the sensor from the proximalposition to the distal position.

In some embodiments, at least one of the first arm and the wall form achannel. The portion of the sensor can be at least partially located inthe channel such that the channel is configured to resist the bucklingforces. The system can comprise a distal protrusion configured to movethe first arm away from the wall to enable the system to move theportion of the sensor from the proximal position to the distal position.The portion of the sensor can comprise a central axis. The first arm canprotrude in a direction within plus or minus 45 degrees of perpendicularto the central axis.

In several embodiments, the system comprises a removable applicatorhaving a telescoping assembly that is removably coupled to the base. Thetelescoping assembly can comprise a first set of tongs configured toresist a first buckling force of a first section of the sensor.

In some embodiments, the telescoping assembly comprises a second set oftongs configured to resist a second buckling force of a second sectionof the sensor. The telescoping assembly can comprise a distal protrusionconfigured to move distally into a first area between the first set oftongs and into a second area between the second set of tongs to expandthe first and second sets of tongs.

In several embodiments, the system comprises a removable applicatorcoupled to the base. The applicator can have a pair of biasing members(e.g., a set of tongs). A portion of the sensor can be located in anarea between the pair of biasing members such that the pair of biasingmembers is configured to resist buckling forces of the sensor.

In some embodiments, the pair of biasing members is held in a compressedstate by a channel configured to enable the pair of biasing members toexpand in response to moving the pair of biasing members far enoughdistally that a distal end of the sensor is located distally relative tothe distal side of the applicator. The pair of biasing members can be aset of tongs.

In several embodiments, the system comprises a first arm and a secondarm that extend distally. A portion of the sensor can be located betweenthe first and second arms such that the first and second arms areconfigured to resist buckling forces of the sensor. The first and secondarms can be located in a channel of the system. The channel can hold thefirst and second arms in a compressed state. The channel can beconfigured such that moving the first and second arms distally causesthe first and second arms to spread apart from each other to facilitatethe system moving the portion of the sensor from a proximal position toa distal position.

In some embodiments, the system comprises a first arm and a second armthat extend distally. The first and second arms can be configured tohave a closed state in which the first and second arms resist bucklingforces of a portion of the sensor located between the first and secondarms. The first and second arms can be configured to have an open stateto enable the system to move the portion of the sensor from a proximalposition to a distal position.

In several embodiments, the system comprises a tube coupled to the base.The tube can comprise a slot from a proximal portion of the tube to adistal portion of the tube. The tube can be configured to resistbuckling forces of the sensor. The slot can be configured to enablemoving a first portion of the sensor distally outside of the tube whilemoving a second portion of the sensor distally inside the tube.

In some embodiments, the system comprises a removable applicator coupledto the base. The applicator can couple the tube to the base such thatthe system is configured to move the base distally relative to the tubeto pierce the skin with a distal end of the sensor. The tube cancomprise a first side of the slot and a second side of the slot. Thefirst and second sides of the slot can be coupled together by a linkageconfigured to break open in response to moving the first portion of thesensor distally. The tube can be at least 4 millimeters long as measuredalong a central axis of the tube.

In several embodiments, the system comprises an applicator having achannel configured to resist buckling forces of the sensor. A distalportion of the sensor can be located inside the channel. A proximalportion of the sensor can be located outside the channel. Anintermediate portion of the sensor can couple the distal and proximalportions of the sensor. The intermediate portion of the sensor can belocated in a slot of the channel.

In some embodiments, the slot is configured to enable the intermediateportion of the sensor to move distally through the slot as the sensormoves from a proximal position to a distal position. The channel cancomprise a central axis oriented distally such that the channel isconfigured to guide the distal portion of the sensor towards the skin.The slot can be oriented radially outward from the central axis.

In several embodiments, the slot comprises at least one linkage thatcouples a first side of the slot to a second side of the slot. The atleast one linkage can be configured to break in response to moving theintermediate portion of the sensor distally through the slot.

In some embodiments, the slot is configured to expand (e.g., widen) inresponse to moving the intermediate portion of the sensor distallythrough the slot.

In some embodiments, a telescoping assembly is coupled to the base. Thetelescoping assembly can comprise a distal portion, a proximal portionslidably coupled to the distal portion, and a spring compressed betweenthe proximal portion and the base. The proximal portion can releasablysecure the sensor in a first proximal starting position such that thespring is configured to push the base and the sensor distally inresponse to the system unlatching the base from the proximal portion.

In several embodiments, the proximal portion of the telescoping assemblycomprises a latch configured to releasably secure the base in a secondproximal starting position. The latch can be configured to release thebase in response to moving the proximal portion distally relative to thedistal portion to enable the spring to push the base and the sensordistally.

In some embodiments, the sensor is configured to move along a first pathfrom the first proximal starting position to a first distal endingposition. The proximal portion can be configured to move along a secondpath from a third proximal starting position to a third distal endingposition. The first path of the sensor can be at least 40 percent longerthan the second path of the proximal portion.

In several embodiments, the system is configured to cause the sensor tomove a first distance in response to the proximal portion moving asecond distance that is at least 50 percent shorter than the firstdistance.

In some embodiments, the proximal portion comprises a distallyprotruding arm having an inward protrusion that passes through a hole ofthe distal portion. The inward protrusion can be coupled to the base tosecure the sensor in the first proximal starting position.

In several embodiments, the system is configured such that moving theproximal portion distally relative to the distal portion causes thedistally protruding arm to flex outward to release the inward protrusionfrom the base to enable the spring to push at least a portion of thesensor into the skin.

In some embodiments, the system is configured to move the sensor a firstdistance in response to moving the proximal portion a second distance tounlatch the base. The first distance can be at least twice as long asthe second distance such that the system is configured to magnify afirst movement of the proximal portion into a larger second movement ofthe sensor and/or the base. The distal portion can comprise a channelconfigured to orient the base as the spring pushes the base distally.

In several embodiments, a first housing is rotatably coupled to thebase. A spring can be compressed between a portion of the first housingand the sensor. The system can be configured to unlatch the sensor fromthe first housing to enable the spring to move the sensor distally inresponse to rotating the first housing relative to the base.

In some embodiments, the first housing comprises a first central axis(e.g., a rotational axis of the first housing). The sensor can comprisea portion configured to pierce the skin. The portion can comprise asecond central axis. The first central axis can be oriented within plusor minus twenty degrees of parallel to the second central axis.

In several embodiments, the spring is a helical spring and/or a conicalspring configured to expand distally to move the sensor distally. Afirst housing can be rotatably coupled to the base. A second housing canbe coupled to the sensor. A spring can be compressed between a proximalend of the first housing and the sensor such that the spring isconfigured to push the second housing and the sensor distally relativeto the base and the first housing in response to rotating the firsthousing relative to the base.

In some embodiments, the second housing is located in an interior areaof the first housing. The first adhesive can be configured to secure thebase to the skin to enable the first housing to rotate relative to thebase and relative to the second housing.

In several embodiments, the first housing comprises a first central axis(e.g., a rotational axis). The sensor can comprise a portion configuredto pierce the skin. The portion can comprise a second central axis. Thefirst central axis can be oriented within plus or minus ten degrees ofparallel to the second central axis.

In some embodiments, the spring is a conical spring configured to expandin response to rotating the first housing relative to the base. Thesystem can comprise a mechanical interlock between the first housing andthe second housing. The mechanical interlock can be configured toreleasably hold the spring in a compressed state such that the sensor isin a proximal starting position. The mechanical interlock can comprise afirst protrusion of the first housing that interferes with distalmovement of a second protrusion of the second housing.

In several embodiments, the mechanical interlock is configured such thatrotating the first protrusion relative to the second protrusion causesthe second protrusion to fall distally off the first protrusion andthereby enables the second housing to move distally relative to thefirst housing. The first protrusion can be oriented radially outward,and the second protrusion can be oriented radially inward. The firstprotrusion can be oriented radially inward, and the second protrusioncan be oriented radially outward. The mechanical interlock can comprisea ridge and a groove configured such that rotating the first housingrelative to the base requires overcoming a torque threshold to move theridge out of the groove.

In some embodiments, the system comprises an interface between thesecond housing and the base. The interface can comprise a ridge locatedin a groove configured to limit rotation of the second housing relativeto the base during rotation of the first housing relative to the base.The interface can be oriented from a proximal portion of the secondhousing to a distal portion of the second housing.

In several embodiments, a removable applicator is coupled to the base.The applicator can comprise a rotating housing configured to push firstand second arms distally. A second adhesive can couple the base to thefirst arm. The second arm can be configured to hold the base in a distalposition while the first arm moves proximally to uncouple the first armfrom the base.

In some embodiments, the applicator comprises a locking mechanismconfigured to prevent the first arm and/or the second arm from movingdistally until the locking mechanism is disengaged. The applicator cancomprise a locking mechanism configured to block rotational movement ofthe rotating housing. The system can be configured to disengage thelocking mechanism in response to linear movement of the rotationalhousing.

In several embodiments, the system comprises a removable applicatorcoupled to the base. The applicator can comprise a first housing, asecond housing rotatably coupled to the first housing, and a torsionspring. The torsion spring can have a first portion coupled to the firsthousing and a second portion coupled to the second housing such that thetorsion spring is configured to rotate the second housing relative tothe first housing.

In some embodiments, the applicator has a first arm slidably coupled tothe first housing and coupled to the second housing such that the firstarm is configured to linearly push the sensor from a proximal startingposition to a distal ending position in response to the second housingrotating relative to the first housing.

In several embodiments, the applicator has a second arm slidably coupledto the first housing and coupled to the second housing such that thesecond arm is configured to block proximal movement of the sensor afterthe sensor has reached the distal ending position as the systemuncouples the first arm from the base.

In some embodiments, a second adhesive couples the first arm to thebase. The first and second arms can be configured to move linearly anddistally in response to rotating the second housing relative to thefirst housing.

In several embodiments, a second arm is configured to block the proximalmovement of the sensor as rotation of the second housing relative to thefirst housing uncouples the second adhesive from the base to enable thefirst arm to move proximally relative to the base and relative to thesecond arm.

In some embodiments, the first arm is coupled to a first linear channel.A first protrusion can couple the first linear channel to the secondhousing. The first linear channel can be configured such that a firstrotational movement of the second housing relative to the first housingcauses a first distal linear movement of the first arm relative to thefirst housing.

In several embodiments, the second arm is coupled to a second channelhaving a curved portion. The first protrusion can couple the secondchannel to the second housing. The second channel can be configured suchthat the first rotational movement of the second housing relative to thefirst housing causes a second distal linear movement of the second armrelative to the first housing.

In some embodiments, the curved portion of the second channel isconfigured such that continued rotational movement of the second housingrelative to the first housing after the sensor has reached the distalending position does not cause proximal movement of the second arm asthe continued rotational movement uncouples the second adhesive from thebase by moving the first arm proximally.

In several embodiments, the second housing is coupled to the firsthousing by a second protrusion about which the second housing isconfigured to rotate relative to the first housing. The second housingcan be slidably coupled to the second protrusion such that the secondhousing is configured to move from a first position to a second positionalong the second protrusion. In the first position, a third protrusioncan block rotational movement of the second housing relative to thefirst housing to impede distal movement of the sensor.

In some embodiments, the system comprises a release mechanism configuredto enable the second housing to rotate relative to the first housing.The release mechanism can comprise a button and/or any suitable trigger.The first housing can comprise a button configured to move the secondhousing from the first position to the second position in which thesecond housing is configured to rotate relative to the first housing tomove the sensor distally.

In several embodiments, a base comprises a proximal portion coupled to adistal portion by flex arms configured to cause the proximal portion torotate relative to the distal portion in response to moving the proximalportion distally (relative to the distal portion) to insert at least aportion of the sensor into the skin. The proximal portion can couple thetransmitter to the distal portion.

In some embodiments, the flex arms comprise at least one living hingeconfigured to rotate the proximal portion relative to the distal portionin response to moving the sensor distally. The flex arms can be spacedaround a distal end of the sensor such that the flex arms are configuredto rotate the distal end as the distal end moves from a proximalstarting position to a distal ending position.

In several embodiments, a removable interference member is locatedbetween the distal portion and the proximal portion such that theremovable interference member is configured to block the system frommoving the sensor from a proximal starting position to a distal endingposition. Removing the interference member can enable the system to movethe sensor to the distal ending position.

In some embodiments, the base comprises a proximal portion coupled to adistal portion by a first arm and a second arm. A distal end portion ofthe sensor comprises a central axis. The first arm can be oriented at afirst angle of plus or minus 45 degrees of perpendicular to the centralaxis. The second arm can be oriented at a second angle of plus or minus45 degrees of perpendicular to the central axis.

In several embodiments, the first and second arms are configured toguide the proximal portion linearly relative to the distal portion asthe proximal portion moves towards the distal portion. The first andsecond arms can be configured to cause the proximal portion to rotaterelative to the distal portion in response to moving the distal endportion of the sensor from a proximal starting position to a distalending position. The second arm can slant away from the first arm suchthat the first and second arms are configured to rotate the distal endportion of the sensor as the system moves the sensor from the proximalstarting position to the distal ending position.

In some embodiments, a base comprises a first portion and a secondportion coupled by a hinge configured such that pivoting the secondportion towards the first portion causes the sensor to move from aproximal starting position to a distal ending position. The secondportion can couple the transmitter to the first portion. The firstportion can couple the first adhesive to the second portion.

In several embodiments, the base can be configured such that decreasinga pivot angle between the first portion and the second portion moves adistal end of the sensor out of a hole of the distal side of the base tofacilitate the distal end piercing the skin. A proximal segment of thesensor can be coupled to the second portion such that the system can beconfigured to move a portion of the sensor out of an area between thefirst and second portions and distally through the hole of the base inresponse to decreasing the pivot angle.

In some embodiments, the base comprises a left half and a right half.The left half can comprise the hole of the base. The right half cancomprise the hinge (such that the hole and the hinge are located ondifferent halves of the base). The hinge can comprise a pin rotatablycoupled to a sleeve configured to retain the pin as the second portionrotates relative to the first portion.

In several embodiments, the base comprises a first portion and a secondportion coupled by a hinge configured such that pivoting the secondportion towards the first portion causes the sensor to move from aproximal starting position to a distal ending position. A spring can becoupled to the base. The spring can be configured to facilitate pivotingthe second portion relative to the first portion. The spring can be atorsional spring, a leaf spring, and/or any other type of springdescribed herein and/or incorporated by reference. The spring can beconfigured to apply a torque about the hinge.

In some embodiments, the system comprises a removable applicator. Theapplicator can comprise a housing; a first arm rotatably coupled to thehousing by a hinge having a hinge axis; a second arm rotatably coupledto the housing about the hinge axis; a first spring configured to rotatethe first arm in a first rotational direction to move the sensor from aproximal starting position to a distal ending position; and a secondspring configured to rotate the second arm in a second rotationaldirection that is opposite to the first rotational direction.

In several embodiments, the second arm is configured to couple the baseto the housing as the first arm rotates in the first rotationaldirection. The first arm can be configured to hold the sensor in thedistal ending position while the second arm uncouples the base from theapplicator by rotating in the second rotational direction.

In some embodiments, the applicator comprises a first mechanicalinterlock that releasably couples the second arm to the base such thatthe first arm is configured to move the second arm and the base in thefirst rotational direction. The first arm can be located at leastpartially between the base and the second arm. The first mechanicalinterlock can comprise a third flex arm that secures the first arm atleast partially between the base and the second arm. The firstmechanical interlock can be configured to uncouple from the base toenable the second arm to rotate in the second rotational direction inresponse to the first arm moving the second arm in the first rotationaldirection.

In several embodiments, the housing (or another portion of theapplicator) comprises a second mechanical interlock configured to holdthe first arm in a distal position while the second arm rotates in thesecond rotational direction. The second mechanical interlock cancomprise a fourth flex arm configured to couple to least a portion ofthe first arm.

In some embodiments, the applicator comprises a fifth flex arm thatcouples the first arm (and/or the second arm) to the housing such thatthe sensor is in the proximal starting position. The fifth flex arm canbe configured to resist a rotational force of the first spring. Aportion of the fifth flex arm can protrude from an exterior of thehousing such that the portion comprises an actuation tab and/or anactuation lever. The fifth flex arm can be configured to uncouple fromthe housing to enable the first arm to rotate in response to moving theactuation tab and/or the actuation lever.

In some embodiments, a sensor system is configured for measuring ananalyte concentration. The sensor system can comprise a base having adistal side configured to face towards a skin of a host; a firstadhesive coupled to the base and configured to couple the base to theskin; a transmitter coupled to the base and configured to transmitanalyte measurement data; and/or a transcutaneous analyte measurementsensor coupled to the base.

In several embodiments, the sensor comprises a distal end portion havinga central axis and a planar profile coincident with the central axis.The planar profile of the distal end portion can be parabolic.

In some embodiments, the distal end portion of the sensor is coated witha membrane. A distal tip of the sensor can be configured to pierce theskin and can be rounded to resist delamination of the membrane.

In several embodiments, the distal end portion of the sensor is coatedwith a membrane. The parabolic distal end portion can be configured toprovide a gradual diameter increase to reduce tissue trauma and toprovide a curved distal tip configured to resist delamination of themembrane. A slope of the parabolic distal end portion can comprise alinear derivative.

In some embodiments, a segment of the sensor is configured to beinserted into the skin. The segment can comprise a first maximum width.The parabolic distal end portion can comprise a second maximum widththat is at least 50 percent of the first maximum width.

In several embodiments, the distal end portion is coated by a membraneconfigured to enable the sensor system to measure a glucose indication.The membrane can comprise a thickness that varies by less than plus orminus 30 percent relative to an average thickness of the membrane.

In some embodiments, the parabolic distal end portion comprises a distalsection and a proximal section. The distal section can comprise a firstangle relative to the central axis. The proximal section can comprise asecond angle relative to the central axis. The first angle can be atleast twice as large as the second angle such that the first angle isconfigured to resist delamination of the membrane and the second angleis configured to gradually increase a width of the profile.

In several embodiments, the sensor comprises a distal end portion havinga central axis and a planar profile coincident with the central axis. Adistal tip of the sensor can be curved such that the planar profilecomprises a curved distal end that couples a first curved side to asecond curved side.

In some embodiments, the distal end portion of the sensor is coated witha membrane. The curved distal end can be configured to resistdelamination of the membrane. The first curved side and the secondcurved side can be configured to provide a smooth transition from thedistal tip to resist delamination and to provide a gradual transitionfrom a first diameter of the distal tip to a maximum diameter of thedistal end portion.

In several embodiments, the sensor is a glucose sensor having aconductive core and a conductive layer configured to enable the systemto apply a voltage between the conductive core and the conductive layerto measure a glucose indication.

In some embodiments, the sensor comprises a first electrical insulationlayer located around a first section of the conductive core. The sensorcan comprise a second electrical insulation layer located around asecond section of the conductive core. The conductive layer can belocated radially outward from the first insulation layer. The firstinsulation layer can be spaced apart from the second insulation layer toform a gap configured to enable the system to apply the voltage betweenthe conductive core and the conductive layer. The sensor can comprise anelectrical insulation cap that covers a distal end of the conductivecore.

In several embodiments, the sensor comprises a distal end portion thatis conical with a rounded distal tip. The rounded distal tip can beconfigured to resist delamination of a membrane that coats the distalend portion. The distal end portion can be conical to facilitatepiercing the skin.

In some embodiments, the sensor comprises a distal end portion that isconical with a blunted tip. The blunted tip can be configured to resistdelamination of a membrane that coats the distal end portion.

In several embodiments, the sensor comprises a distal end portion havinga central axis and a planar profile coincident with the central axis. Adistal tip of the sensor can be curved such that the planar profilecomprises a curved distal end that couples a first straight side to asecond straight side.

In some embodiments, the distal end portion can be coated by a membrane.The distal tip can be curved such that the distal tip is configured toresist delamination of the membrane. The first and second sides can bestraight such that the sides are configured to linearly increase adiameter of the distal end portion to reduce tissue trauma caused byinserting the distal end portion into the skin.

In several embodiments, the curved distal end comprises a radius that isgreater than 10 micrometers and less than 35 micrometers such that thecurved distal end is configured to be large enough to resistdelamination of a membrane that coats the curved distal end and smallenough to reduce patient discomfort associated with piercing of theskin.

In some embodiments, the curved distal end comprises a maximum widththat is greater than 10 micrometers and less than 35 micrometers suchthat the curved distal end is configured to be large enough to resistdelamination of a membrane that coats the curved distal end and smallenough to reduce patient discomfort associated with piercing of theskin. An angle between the first and second straight sides can begreater than 15 degrees and less than 25 degrees such that the angle isconfigured to reduce patient discomfort associated with piercing of theskin.

In several embodiments, the sensor comprises a distal end portion havinga central axis and a planar profile coincident with the central axis.The planar profile can comprise a left portion having a first sidecoupled to a second side. The planar profile can comprise a rightportion having a third side coupled to a fourth side. A first anglebetween the first side and the third side can be smaller than a secondangle between the second side and the fourth side such that a proximalsection of the end portion provides a more gradual width increase than adistal section of the end portion. The first, second, third, and fourthsides can be straight. The first, second, third, and fourth sides can becurved.

In some embodiments, a curved distal end couples the second side to thefourth side. The curved distal end can be configured to resistdelamination of a membrane that coats the distal end portion of thesensor.

In several embodiments, the sensor is a glucose sensor comprising amembrane that coats the distal end portion of the sensor. The distal endportion can be configured to resist delamination of the membrane, reducetissue trauma, and/or reduce patient discomfort caused by piercing theskin.

In some embodiments, the sensor comprises a distal end portion having acentral axis and a first facet oriented at a first angle of less than 25degrees relative to the central axis such that the first facet isconfigured to facilitate piercing the skin. The distal end portion ofthe sensor can comprise a second facet oriented at a second angle ofless than 25 degrees relative to the central axis. The first facet canbe oriented at a third angle relative to the second facet. The thirdangle can be greater than 10 degrees and less than 25 degrees.

In several embodiments, the first and second facets form a wedgeconfigured to facilitate piercing the skin. The distal end portion ofthe sensor can be coated by a membrane. A rounded ridge can couple thefirst facet to the second facet such that the rounded ridge isconfigured to resist delamination of the membrane.

In some embodiments, the distal end portion of the sensor comprises athird facet oriented at a fourth angle of less than 25 degrees relativeto the central axis. The first, second, and third facets can form atriangular pyramid configured to facilitate piercing the skin. Thedistal end portion of the sensor can be coated by a membrane. Thetriangular pyramid can comprise a rounded distal tip configured toresist delamination of the membrane.

In several embodiments, a first rounded ridge couples the first facet tothe second facet. A second rounded ridge can couple the second facet tothe third facet. The first rounded ridge and the second rounded ridgecan be configured to reduce tissue trauma caused by inserting the distalend portion of the sensor into the host.

In some embodiments, the distal end portion of the sensor comprises afourth facet oriented at a fifth angle of less than 25 degrees relativeto the central axis. The first, second, third, and fourth facets canform a rectangular pyramid configured to facilitate piercing the skin.

In some embodiments, the sensor comprises a conductive distal endportion coated by a membrane. The conductive distal end portion cancomprise a first step configured to resist proximal movement of themembrane relative to the first step.

In several embodiments, the sensor comprises a tapered end sectioncoated by a membrane and having a distal tip. The tapered end sectioncan comprise a first step configured to resist proximal movement of themembrane relative to the first step.

In some embodiments, the sensor comprises a tapered end section coatedby a membrane. The tapered end section comprises the distal tip of thesensor. The sensor comprises a first step located within plus or minus 1millimeter and/or within plus or minus 2.1 millimeters of the taperedend section. The first step can be configured to resist proximalmovement of the membrane relative to the first step.

In several embodiments, the sensor is coated by a membrane. A portion ofthe sensor can comprise a first step. The sensor can comprise a grooveconfigured to be inserted into tissue of the host. The first step can belocated distally relative to the groove. The first step can beconfigured to resist proximal movement of the membrane relative to thefirst step.

In several embodiments, the sensor comprises a portion coated by amembrane. The portion of the sensor can comprise a first conductivelayer electrically insulated from a second conductive layer by aninsulation layer. The first conductive layer can be configured to beelectrically coupled to the second conductive layer via tissue of thehost. The first conductive layer can extend farther distally than thesecond conductive layer. The first conductive layer can comprise a firststep configured to resist proximal movement of the membrane relative tothe first step. The first step can be located farther distally than thesecond conductive layer.

In some embodiments, a distal portion of the sensor comprises a firststep and a second step. The second step can be spaced proximallyrelative to the first step. The distal portion of the sensor can becoated by a membrane. The first step and the second step can facedistally. The first step can be configured to resist proximal movementof the membrane relative to the first step.

In several embodiments, the first step comprises a surface orientedwithin plus or minus 25 degrees of perpendicular to a central axis ofthe portion of the sensor. The first step can comprise a surfaceoriented within plus or minus 15 degrees of perpendicular to a centralaxis of the portion of the sensor. The surface can form an interferencefeature configured to impede proximal movement of the membrane relativeto the surface by causing a compressive force within the membrane inresponse to the proximal movement of the membrane.

In some embodiments, the sensor can comprise a first conductive layerelectrically insulated from a second conductive layer by an insulationlayer. The first conductive layer can be conductively coupled to theconductive distal end portion such that the conductive distal endportion is configured to be conductively coupled to the secondconductive layer via tissue of the host.

In several embodiments, a sensor comprises a distal end portion coatedby a membrane. The distal end portion can comprise a gap between aconductive core and a conductive layer of the sensor. The gap can beconfigured to enable a subcutaneous current between the conductive coreand the conductive layer. The distal end portion can comprise a steplocated distally relative to the gap and configured to resist proximalmovement of the membrane relative to the step.

In some embodiments, the step can comprise a surface oriented withinplus or minus 25 degrees of perpendicular to a central axis of thedistal end portion. The surface can form an interference featureconfigured to impede proximal movement of the membrane relative to thesurface by causing a compressive force within the membrane in responseto the proximal movement of the membrane. The conductive core cancomprise the step. An insulation layer located around the conductivecore can form the step.

In several embodiments, the distal end portion comprises at least one ofa rounded distal tip, a parabolic shape, a conical shape, a wedge shape,a triangular pyramid shape, and a rectangular pyramid shape such thatthe distal end portion is configured to facilitate piercing the skin.

In some embodiments, the sensor comprises a distal end portion coated bya membrane. The distal end portion of the sensor can comprise a centralaxis, a distal tip, and a distally facing surface spaced proximallyapart from the distal tip. The distally facing surface can form amechanical interlock with the membrane such that the mechanicalinterlock is configured to impede proximal movement of the membranerelative to the distally facing surface.

In several embodiments, the sensor can comprise a conductive core, aconductive layer, and an insulation layer configured to electricallyinsulate the conductive core from the conductive layer. The conductivecore can extend farther distally than the insulation layer to form ashortest conduction path between the conductive core and the conductivelayer. The distally facing surface can be located distally relative tothe shortest conduction path.

In some embodiments, the sensor comprises a conductive core and aconductive layer configured to enable the system to apply a voltagebetween the conductive core and the conductive layer to measure ananalyte indication. The sensor can comprise a first electricalinsulation layer located around a first section of the conductive coreand a second electrical insulation layer located around a second sectionof the conductive core. The conductive layer can be located radiallyoutward from the first insulation layer. The first insulation layer canbe spaced apart from the second insulation layer to form a gapconfigured to enable the system to apply the voltage between theconductive core and the conductive layer. The distally facing surfacecan be located distally relative to the gap. The distally facing surfacecan be oriented within a range of plus or minus 20 degrees relative toperpendicular to the central axis.

Any of the features of each embodiment is applicable to all aspects andembodiments identified herein. Moreover, any of the features of anembodiment is independently combinable, partly or wholly with otherembodiments described herein in any way (e.g., one, two, three, or moreembodiments may be combinable in whole or in part). Further, any of thefeatures of an embodiment may be made optional to other aspects orembodiments. Any aspect or embodiment of a method can be performed by asystem or apparatus of another aspect or embodiment, and any aspect orembodiment of a system can be configured to perform a method of anotheraspect or embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages are described belowwith reference to the drawings, which are intended to illustrate, butnot to limit, the invention. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments.

FIG. 1 illustrates a schematic view of an analyte sensor system,according to some embodiments.

FIG. 2 illustrates a perspective view of a sensor system, according tosome embodiments.

FIG. 3 illustrates a cross-sectional view along line 3-3 from FIG. 2,according to some embodiments.

FIG. 4 illustrates a cross-sectional view like FIG. 3 except that thearm has been moved, according to some embodiments.

FIG. 5 illustrates a perspective view of a system, according to someembodiments.

FIG. 6 illustrates a cross-sectional view along line 6-6 from FIG. 5,according to some embodiments.

FIG. 7 illustrates the same cross-sectional view as shown in FIG. 6except that the sensor has been retracted, according to someembodiments.

FIG. 8 illustrates a perspective view of a system with a spring-loadedarm, according to some embodiments.

FIG. 9 illustrates a cross-sectional view from the perspective shown inFIG. 8, according to some embodiments.

FIG. 10 illustrates the same cross-sectional view as illustrated in FIG.9 except that the sensor has been retracted, according to someembodiments.

FIG. 11 illustrates a perspective view of an embodiment with aspring-loaded arm, according to some embodiments.

FIG. 12 illustrates a cross-sectional, perspective view of theembodiment shown in FIG. 11, according to some embodiments.

FIG. 13 illustrates a cross-sectional, perspective view of theembodiment shown in FIG. 12 except that the arm has moved relative tothe base, according to some embodiments.

FIG. 14 illustrates a perspective view of a system with an arm rotatablycoupled to a base, according to some embodiments.

FIG. 15 illustrates a side, cross-sectional view of the system shown inFIG. 14, according to some embodiments.

FIG. 16 illustrates a perspective view of the system shown in FIG. 14,according to some embodiments.

FIG. 17 illustrates a perspective view of a system that includes a hingeconfigured to retract a sensor, according to some embodiments.

FIG. 18 illustrates a side, cross-sectional view of the system in astate prior to sensor retraction, according to some embodiments.

FIG. 19 illustrates a side, cross-sectional view of the system in astate after sensor retraction, according to some embodiments.

FIG. 20 illustrates a perspective view of a base that comprises a firstportion and a second portion, according to some embodiments.

FIG. 21 illustrates a perspective view of the base after the firstportion illustrated in FIG. 20 has rotated, according to someembodiments.

FIG. 22a illustrates a top view of the system illustrated in FIG. 20,according to some embodiments.

FIG. 22b illustrates a side view of the system illustrated in FIG. 20,according to some embodiments.

FIGS. 23 and 24 illustrate perspective views of a sensor system thatincludes a pliable sheet, according to some embodiments.

FIG. 25 illustrates a perspective view of the pliable sheet as thepliable sheet is unfolded, according to some embodiments.

FIG. 26 illustrates a side view of the pliable sheet, according to someembodiments.

FIG. 27 illustrates a perspective view of the pliable sheet as thepliable sheet covers a sensor tip, according to some embodiments.

FIG. 28 illustrates a top view of a system configured to retract asensor, according to some embodiments.

FIG. 29 illustrates a perspective view of the system illustrated in FIG.28, according to some embodiments.

FIG. 30 illustrates a perspective view of the system after the sensorhas been retracted into a housing, according to some embodiments.

FIGS. 31 and 32 illustrate a side view of a system that comprises anextendable sensor cover, according to some embodiments.

FIGS. 33 and 34 illustrate perspective views of a system 202 k,according to some embodiments.

FIG. 35 illustrates a perspective view of a system, according to someembodiments.

FIG. 36 illustrates a side, cross-sectional view of the system shown inFIG. 35, according to some embodiments.

FIG. 37 illustrates a side view of the system, according to someembodiments.

FIG. 38 illustrates a perspective view of a sensor system moving towardsa tool, according to some embodiments.

FIG. 39 illustrates a perspective, cross-sectional view of the sensorysystem moving towards the tool, according to some embodiments.

FIG. 40 illustrates a side, cross-sectional view of the system,according to some embodiments.

FIG. 41 illustrates a perspective view of the system, according to someembodiments.

FIG. 42 illustrates a perspective view of the system, according to someembodiments.

FIG. 43 illustrates a top view of the system, according to someembodiments.

FIG. 44 illustrates a perspective, cross-sectional view along line 44-44from FIG. 43, according to some embodiments.

FIG. 45 illustrates a perspective, cross-sectional view, according tosome embodiments.

FIG. 46 illustrates a side, cross-sectional view taken along line 46-46from FIG. 43, according to some embodiments.

FIG. 47 illustrates a perspective view of the cross section shown inFIG. 46, according to some embodiments.

FIG. 48 illustrates a perspective view of a system, according to someembodiments.

FIGS. 49 and 50 illustrate side, cross-sectional views of the system,according to some embodiments.

FIG. 51 illustrates a side, cross-sectional view of a system with abiased sensor, according to some embodiments.

FIGS. 52 and 53 illustrate side, cross-sectional views of a telescopingapplicator, according to some embodiments.

FIGS. 54-56 illustrate equations, according to some embodiments.

FIG. 57 illustrates a perspective view of a system with a collapsiblesupport, according to some embodiments.

FIGS. 58 and 59 illustrate side views of the system, according to someembodiments.

FIG. 60 illustrates a perspective view of a system, according to someembodiments.

FIG. 61 illustrates a side view of the system prior to collapsingbellows, according to some embodiments.

FIGS. 62 and 63 illustrate side, cross-sectional views, according tosome embodiments.

FIGS. 64 and 65 illustrate perspective views of a system, according tosome embodiments.

FIG. 66 illustrates a side view of a housing, according to someembodiments.

FIG. 67 illustrates a perspective view of the system without thehousing, according to some embodiments.

FIG. 68 illustrates a perspective view of a system, according to someembodiments.

FIGS. 69 and 70 illustrate side, cross-sectional views of the system,according to some embodiments.

FIG. 71 illustrates a perspective view of a system, according to someembodiments.

FIG. 72 illustrates a perspective, cross-sectional view of the system,according to some embodiments.

FIG. 73 illustrates a side, cross-sectional view of the system,according to some embodiments.

FIG. 74 illustrates a side view of a base, according to someembodiments.

FIG. 75 illustrates a perspective, cross-sectional view of a telescopingapplicator, according to some embodiments.

FIGS. 76 and 77 illustrate side, cross-sectional views of the system,according to some embodiments.

FIG. 78 illustrates a perspective view of a system, according to someembodiments.

FIGS. 79-81 illustrate side, cross-sectional views of the system,according to some embodiments.

FIG. 82 illustrates a perspective view of a system, according to someembodiments.

FIG. 83 illustrates a side, cross-sectional view of the system,according to some embodiments.

FIG. 84 illustrates a partial, perspective view from the perspectiveshown in FIG. 82, according to some embodiments.

FIG. 85 illustrates a perspective view of an applicator, according tosome embodiments.

FIGS. 86-88 illustrate side, cross-sectional views of a system,according to some embodiments.

FIG. 89 illustrates a perspective view of a system, according to someembodiments.

FIG. 90 illustrates a perspective view of a portion of the system,according to some embodiments.

FIG. 91 illustrates a top, cross-sectional view of the system, accordingto some embodiments.

FIGS. 92 and 93 illustrate side, perspective, cross-sectional views ofthe system, according to some embodiments.

FIG. 94 illustrates a side view of an applicator, according to someembodiments.

FIGS. 95-98 illustrate perspective, cross-sectional views of a system,according to some embodiments.

FIGS. 99 and 100 illustrate side views of portions of the system,according to some embodiments.

FIG. 101 illustrates a perspective view of a system, according to someembodiments.

FIG. 102 illustrates a side, cross-sectional view of the system,according to some embodiments.

FIGS. 103-106 illustrate perspective views of the system, according tosome embodiments.

FIG. 107 illustrates a sensor insertion chart and distal portions ofsensors, according to some embodiments.

FIG. 108 illustrates a side view of a distal portion of a sensor,according to some embodiments.

FIG. 109 illustrates a perspective view of a distal portion of a sensor,according to some embodiments.

FIG. 110 illustrates a side view of a distal portion of a sensor,according to some embodiments.

FIG. 111 illustrates a perspective view of a distal portion of a sensor,according to some embodiments.

FIG. 112 illustrates a side view of distal portions of sensors,according to some embodiments.

FIG. 113 illustrates a bottom view of distal portions of sensors,according to some embodiments.

FIG. 114 illustrates a perspective view of distal portions of sensors,according to some embodiments.

FIGS. 115-117 illustrate side views of distal portions of sensors,according to some embodiments.

FIG. 118 illustrates a side view of distal portions of sensors,according to some embodiments.

FIG. 119 illustrates a bottom view of distal portions of sensors,according to some embodiments.

FIG. 120 illustrates a perspective view of distal portions of sensors,according to some embodiments.

FIG. 121 illustrates a bottom view of a sensor, according to someembodiments.

FIGS. 122 and 123 illustrate perspective views of a distal portion ofthe sensor, according to some embodiments.

FIG. 124 illustrates a side view of a distal portion of a sensor,according to some embodiments.

FIG. 125 illustrates a cross-sectional view along line 125-125 from FIG.124, according to some embodiments.

FIG. 126 illustrates a cross-sectional view along line 126-126 from FIG.116, according to some embodiments.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, inventivesubject matter extends beyond the specifically disclosed embodiments toother alternative embodiments and/or uses, and to modifications andequivalents thereof. Thus, the scope of the claims appended hereto isnot limited by any of the particular embodiments described below. Forexample, in any method or process disclosed herein, the acts oroperations of the method or process may be performed in any suitablesequence and are not necessarily limited to any particular disclosedsequence. Various operations may be described as multiple discreteoperations in turn, in a manner that may be helpful in understandingcertain embodiments; however, the order of description should not beconstrued to imply that these operations are order dependent.Additionally, the structures, systems, and/or devices described hereinmay be embodied as integrated components or as separate components.

For purposes of comparing various embodiments, certain aspects andadvantages of these embodiments are described. Not necessarily all suchaspects or advantages are achieved by any particular embodiment. Thus,for example, various embodiments may be carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other aspects or advantages as mayalso be taught or suggested herein.

System Introduction

U.S. Patent Publication No. US-2013-0267811-A1, the entire contents ofwhich are incorporated by reference herein, explains how FIG. 1 is aschematic of a continuous analyte sensor system 100 attached to a host(e.g., a person). The analyte sensor system 100 communicates with otherdevices 110-113 (which can be located remotely from the host). Atranscutaneous analyte sensor system 102 comprising an on-skin sensorassembly 600 is coupled to the skin of a host by a base (not shown),which can be a disposable housing having several parts that can moverelative to each other.

Any of the features described in the context of FIG. 1 can be applicableto all aspects and embodiments identified herein. For example, theembodiments described in the context of FIG. 1 can be combined with theembodiments described in the context of FIGS. 2-126. Moreover, any ofthe features of an embodiment is independently combinable, partly orwholly with other embodiments described herein in any way (e.g., one,two, three, or more embodiments may be combinable in whole or in part).Further, any of the features of an embodiment may be made optional toother aspects or embodiments. Any aspect or embodiment of a method canbe performed by a system or apparatus of another aspect or embodiment,and any aspect or embodiment of a system can be configured to perform amethod of another aspect or embodiment.

Referring now to FIG. 1, the system 102 includes a transcutaneousanalyte sensor 200 and an electronics unit (referred to interchangeablyas “sensor electronics” or “transmitter”) 500 for wirelesslytransmitting analyte information to a receiver. Transmitters can beremovably coupled to a base (e.g., by the user). In some embodiments,the transmitter is not removable (e.g., by the user). Transmitters canbe integrated into a base (e.g., at the factory).

The receiver can be located remotely relative to the system 102. In someembodiments, the receiver includes a display screen, which can displayinformation to a person such as the host. Example receivers includecomputers such as smartphones, smartwatches, tablet computers, laptopcomputers, and desktop computers. In some embodiments, receivers can beApple Watches, iPhones, and iPads made by Apple Inc. In still furtherembodiments, the system 102 can be configured for use in applying a drugdelivery device, such an infusion device, to the skin of a patient. Insuch embodiments, the system can include a catheter instead of, or inaddition to, a sensor, the catheter being connected to an infusion pumpconfigured to deliver liquid medicines or other fluids into thepatient's body. In embodiments, the catheter can be deployed into theskin in much the same manner as a sensor would be, for example asdescribed herein.

In some embodiments, the receiver is mechanically coupled to theelectronics unit 500 to enable the receiver to receive data (e.g.,analyte data) from the electronics unit 500. To increase the convenienceto users, in several embodiments, the receiver does not need to bemechanically coupled to the electronics unit 500 and can even receivedata from the electronics unit 500 over great distances (e.g., when thereceiver is many feet or even many miles from the electronics unit 500).

During use, a sensing portion of the sensor 200 can be under the host'sskin and a contact portion of the sensor 200 can be electricallyconnected to the electronics unit 500. The electronics unit 500 can beengaged with a housing (e.g., a base) which is attached to an adhesivepatch fastened to the skin of the host.

The on-skin sensor assembly 600 may be attached to the host with use ofan applicator adapted to provide convenient and secure application. Suchan applicator may also be used for attaching the electronics unit 500 toa base, inserting the sensor 200 through the host's skin, and/orconnecting the sensor 200 to the electronics unit 500. Once theelectronics unit 500 is engaged with the base and the sensor 200 hasbeen inserted into the skin (and is connected to the electronics unit500), the sensor assembly can detach from the applicator.

The continuous analyte sensor system 100 can include a sensorconfiguration that provides an output signal indicative of aconcentration of an analyte. The output signal including (e.g., sensordata, such as a raw data stream, filtered data, smoothed data, and/orotherwise transformed sensor data) is sent to the receiver.

In some embodiments, the analyte sensor system 100 includes atranscutaneous glucose sensor, such as is described in U.S. PatentPublication No. US-2011-0027127-A1, the entire contents of which arehereby incorporated by reference. In some embodiments, the sensor system100 includes a continuous glucose sensor and comprises a transcutaneoussensor (e.g., as described in U.S. Pat. No. 6,565,509, as described inU.S. Pat. No. 6,579,690, as described in U.S. Pat. No. 6,484,046). Thecontents of U.S. Pat. No. 6,565,509, U.S. Pat. No. 6,579,690, and U.S.Pat. No. 6,484,046 are hereby incorporated by reference in theirentirety.

In several embodiments, the sensor system 100 includes a continuousglucose sensor and comprises a refillable subcutaneous sensor (e.g., asdescribed in U.S. Pat. No. 6,512,939). In some embodiments, the sensorsystem 100 includes a continuous glucose sensor and comprises anintravascular sensor (e.g., as described in U.S. Pat. No. 6,477,395, asdescribed in U.S. Pat. No. 6,424,847). The contents of U.S. Pat. No.6,512,939, U.S. Pat. No. 6,477,395, and U.S. Pat. No. 6,424,847 arehereby incorporated by reference in their entirety.

Various signal processing techniques and glucose monitoring systemembodiments suitable for use with embodiments described herein aredescribed in U.S. Patent Publication No. US -2005-0203360-A1 and U.S.Patent Publication No. US -2009-0192745-A1, the contents of which arehereby incorporated by reference in their entirety. The sensor canextend through a housing, which can maintain the sensor on the skin andcan provide for electrical connection of the sensor to sensorelectronics, which can be provided in the electronics unit 500.

In several embodiments, the sensor is formed from a wire or is in a formof a wire. A distal end of the wire can be sharpened to form a conicalshape (to facilitate inserting the wire into the tissue of the host).The sensor can include an elongated conductive body, such as a bareelongated conductive core (e.g., a metal wire) or an elongatedconductive core coated with one, two, three, four, five, or more layersof material, each of which may or may not be conductive. The elongatedsensor may be long and thin, yet flexible and strong. For example, insome embodiments, the smallest dimension (e.g., a diameter) of theelongated conductive body is less than 0.1 inches, less than 0.075inches, less than 0.05 inches, less than 0.025 inches, less than 0.01inches, less than 0.004 inches, and/or less than 0.002 inches.

The sensor may have a circular cross section. In some embodiments, thecross section of the sensor and/or the elongated conductive body can beovoid, rectangular, triangular, polyhedral, star-shaped, C-shaped,T-shaped, X-shaped, Y-shaped, irregular, or the like. In someembodiments, a conductive wire electrode is employed as a core. To suchan electrode, one or two additional conducting layers may be added(e.g., with intervening insulating layers provided for electricalisolation). The conductive layers can be comprised of any suitablematerial. In certain embodiments, it may be desirable to employ aconductive layer comprising conductive particles (i.e., particles of aconductive material) in a polymer or other binder.

In some embodiments, the materials used to form the elongated conductivebody (e.g., stainless steel, titanium, tantalum, platinum,platinum-iridium, iridium, certain polymers, and/or the like) can bestrong and hard, and therefore can be resistant to breakage. Forexample, in several embodiments, the ultimate tensile strength of theelongated conductive body is greater than 80 kPsi and less than 500kPsi, and/or the Young's modulus of the elongated conductive body isgreater than 160 GPa and less than 220 GPa. In some embodiments, theyield strength of the elongated conductive body can be greater than 60kPsi and less than 2200 kPsi.

The electronics unit 500 can be releasably coupled to the sensor 200.The electronics unit 500 can include electronic circuitry associatedwith measuring and processing the continuous analyte sensor data. Theelectronics unit 500 can be configured to perform algorithms associatedwith processing and calibration of the sensor data. For example, theelectronics unit 500 can provide various aspects of the functionality ofa sensor electronics module as described in U.S. Patent Publication No.US-2009-0240120-A1 and U.S. Patent Publication No. US-2012-0078071-A1,the entire contents of which are incorporated by reference herein. Theelectronics unit 500 may include hardware, firmware, and/or softwarethat enable measurement of levels of the analyte via a glucose sensor,such as an analyte sensor 200.

For example, the electronics unit 500 can include a potentiostat, apower source for providing power to the sensor 200, signal processingcomponents, data storage components, and a communication module (e.g., atelemetry module) for one-way or two-way data communication between theelectronics unit 500 and one or more receivers, repeaters, and/ordisplay devices, such as devices 110-113. Electronics can be affixed toa printed circuit board (PCB), or the like, and can take a variety offorms. The electronics can take the form of an integrated circuit (IC),such as an Application-Specific Integrated Circuit (ASIC), amicrocontroller, and/or a processor. The electronics unit 500 mayinclude sensor electronics that are configured to process sensorinformation, such as storing data, analyzing data streams, calibratinganalyte sensor data, estimating analyte values, comparing estimatedanalyte values with time-corresponding measured analyte values,analyzing a variation of estimated analyte values, and the like.Examples of systems and methods for processing sensor analyte data aredescribed in more detail in U.S. Pat. No. 7,310,544, U.S. Pat. No.6,931,327, U.S. Patent Publication No. 2005-0043598-A1, U.S. PatentPublication No. 2007-0032706-A1, U.S. Patent Publication No.2007-0016381-A1, U.S. Patent Publication No. 2008-0033254-A1, U.S.Patent Publication No. 2005-0203360-A1, U.S. Patent Publication No.2005-0154271-A1, U.S. Patent Publication No. 2005-0192557-A1, U.S.Patent Publication No. 2006-0222566-A1, U.S. Patent Publication No.2007-0203966-A1 and U.S. Patent Publication No. 2007-0208245-A1, thecontents of which are hereby incorporated by reference in theirentirety.

One or more repeaters, receivers and/or display devices, such as a keyfob repeater 110, a medical device receiver 111 (e.g., an insulindelivery device and/or a dedicated glucose sensor receiver), asmartphone 112, a portable computer 113, and the like can becommunicatively coupled to the electronics unit 500 (e.g., to receivedata from the electronics unit 500). The electronics unit 500 can alsobe referred to as a transmitter. In some embodiments, the devices110-113 transmit data to the electronics unit 500. The sensor data canbe transmitted from the sensor electronics unit 500 to one or more ofthe key fob repeater 110, the medical device receiver 111, thesmartphone 112, the portable computer 113, and the like. In someembodiments, analyte values are displayed on a display device.

The electronics unit 500 may communicate with the devices 110-113,and/or any number of additional devices, via any suitable communicationprotocol. Example communication protocols include radio frequency;Bluetooth; universal serial bus; any of the wireless local area network(WLAN) communication standards, including the IEEE 802.11, 802.15,802.20, 802.22 and other 802 communication protocols; ZigBee; wireless(e.g., cellular) telecommunication; paging network communication;magnetic induction; satellite data communication; and/or a proprietarycommunication protocol.

Additional sensor information is described in U.S. Pat. No. 7,497,827and U.S. Pat. No. 8,828,201. The entire contents of U.S. Pat. No.7,497,827 and U.S. Pat. No. 8,828,201 are incorporated by referenceherein.

Any sensor shown and/or described herein can be an analyte sensor, aglucose sensor, and/or any other suitable sensor. A sensor described inthe context of any embodiment can be any sensor described herein and/orincorporated by reference. Sensors shown or described herein can beconfigured to sense, measure, detect, and/or interact with any analyte.

As used herein, the term “analyte” is a broad term, and is to be givenits ordinary and customary meaning to a person of ordinary skill in theart (and is not to be limited to a special or customized meaning), andrefers without limitation to a substance or chemical constituent in abiological fluid (for example, blood, interstitial fluid, cerebralspinal fluid, lymph fluid, urine, sweat, saliva, etc.) that can beanalyzed. Analytes can include naturally occurring substances,artificial substances, metabolites, or reaction products.

In some embodiments, the analyte for measurement by the sensing regions,devices, systems, and methods is glucose. However, other analytes arecontemplated as well, including, but not limited to ketone bodies;Acetyl Co A; acarboxyprothrombin; acylcarnitine; adenine phosphoribosyltransferase; adenosine deaminase; albumin; alpha-fetoprotein; amino acidprofiles (arginine (Krebs cycle), histidine/urocanic acid, homocysteine,phenylalanine/tyrosine, tryptophan); andrenostenedione; antipyrine;arabinitol enantiomers; arginase; benzoylecgonine (cocaine);biotinidase; biopterin; c-reactive protein; carnitine; carnosinase; CD4;ceruloplasmin; chenodeoxycholic acid; chloroquine; cholesterol;cholinesterase; cortisol; testosterone; choline; creatine kinase;creatine kinase MM isoenzyme; cyclosporin A; d-penicillamine;de-ethylchloroquine; dehydroepiandrosterone sulfate; DNA (acetylatorpolymorphism, alcohol dehydrogenase, alpha 1-antitrypsin, cysticfibrosis, Duchenne/Becker muscular dystrophy, glucose-6-phosphatedehydrogenase, hemoglobin A, hemoglobin S, hemoglobin C, hemoglobin D,hemoglobin E, hemoglobin F, D-Punjab, beta-thalassemia, hepatitis Bvirus, HCMV, HIV−1, HTLV−1, Leber hereditary optic neuropathy, MCAD,RNA, PKU, Plasmodium vivax, sexual differentiation, 21-deoxycortisol);desbutylhalofantrine; dihydropteridine reductase; diptheria/tetanusantitoxin; erythrocyte arginase; erythrocyte protoporphyrin; esterase D;fatty acids/acylglycines; triglycerides; glycerol; free 13-humanchorionic gonadotropin; free erythrocyte porphyrin; free thyroxine(FT4); free tri-iodothyronine (FT3); fumarylacetoacetase;galactose/gal-1-phosphate; galactose-1-phosphate uridyltransferase;gentamicin; glucose-6-phosphate dehydrogenase; glutathione; glutathioneperioxidase; glycocholic acid; glycosylated hemoglobin; halofantrine;hemoglobin variants; hexosaminidase A; human erythrocyte carbonicanhydrase I; 17-alpha-hydroxyprogesterone; hypoxanthine phosphoribosyltransferase; immunoreactive trypsin; lactate; lead; lipoproteins ((a),B/A-1, β); lysozyme; mefloquine; netilmicin; phenobarbitone; phenytoin;phytanic/pristanic acid; progesterone; prolactin; prolidase; purinenucleoside phosphorylase; quinine; reverse tri-iodothyronine (rT3);selenium; serum pancreatic lipase; sissomicin; somatomedin C; specificantibodies (adenovirus, anti-nuclear antibody, anti-zeta antibody,arbovirus, Aujeszky's disease virus, dengue virus, Dracunculusmedinensis, Echinococcus granulosus, Entamoeba histolytica, enterovirus,Giardia duodenalisa, Helicobacter pylori, hepatitis B virus, herpesvirus, HIV-1, IgE (atopic disease), influenza virus, Leishmaniadonovani, leptospira, measles/mumps/rubella, Mycobacterium leprae,Mycoplasma pneumoniae, Myoglobin, Onchocerca volvulus, parainfluenzavirus, Plasmodium falciparum, poliovirus, Pseudomonas aeruginosa,respiratory syncytial virus, rickettsia (scrub typhus), Schistosomamansoni, Toxoplasma gondii, Trepenoma pallidium, Trypanosomacruzi/rangeli, vesicular stomatis virus, Wuchereria bancrofti, yellowfever virus); specific antigens (hepatitis B virus, HIV-1); acetone(e.g., succinylacetone); acetoacetic acid; sulfadoxine; theophylline;thyrotropin (TSH); thyroxine (T4); thyroxine-binding globulin; traceelements; transferrin; UDP-galactose-4-epimerase; urea; uroporphyrinogenI synthase; vitamin A; white blood cells; and zinc protoporphyrin.

Salts, sugar, protein, fat, vitamins, and hormones naturally occurringin blood or interstitial fluids can also constitute analytes in certainembodiments. The analyte can be naturally present in the biologicalfluid or endogenous, for example, a metabolic product, a hormone, anantigen, an antibody, and the like. Alternatively, the analyte can beintroduced into the body or exogenous, for example, a contrast agent forimaging, a radioisotope, a chemical agent, a fluorocarbon-basedsynthetic blood, or a drug or pharmaceutical composition, including butnot limited to insulin; glucagon; ethanol; cannabis (marijuana,tetrahydrocannabinol, hashish); inhalants (nitrous oxide, amyl nitrite,butyl nitrite, chlorohydrocarbons, hydrocarbons); cocaine (crackcocaine); stimulants (amphetamines, methamphetamines, Ritalin, Cylert,Preludin, Didrex, PreState, Voranil, Sandrex, Plegine); depressants(barbiturates, methaqualone, tranquilizers such as Valium, Librium,Miltown, Serax, Equanil, Tranxene); hallucinogens (phencyclidine,lysergic acid, mescaline, peyote, psilocybin); narcotics (heroin,codeine, morphine, opium, meperidine, Percocet, Percodan, Tussionex,Fentanyl, Darvon, Talwin, Lomotil); designer drugs (analogs of fentanyl,meperidine, amphetamines, methamphetamines, and phencyclidine, forexample, Ecstasy); anabolic steroids; and nicotine. The metabolicproducts of drugs and pharmaceutical compositions are also contemplatedanalytes. Analytes such as neurochemicals and other chemicals generatedwithin the body can also be analyzed, such as, for example, ascorbicacid, uric acid, dopamine, noradrenaline, 3-methoxytyramine (3MT),3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA),5-hydroxytryptamine (5HT), 5-hydroxyindoleacetic acid (FHIAA), andintermediaries in the Citric Acid Cycle.

Embodiments can use a needle to facilitate inserting a sensor intotissue of a host. Some embodiments are illustrated without a needle, butcan be combined with other needle embodiments to include a needle. Someembodiments do not use a needle, but include a sensor and/or anotherportion configured to facilitate piercing the skin of the host. Eachembodiment can be configured to use a needle and can be configured tonot use a needle.

Many embodiments described herein use an adhesive. One purpose of theadhesive can be to couple a base, a sensor module, and/or a sensor to ahost (e.g., to skin of the host). The adhesive can be configured foradhering to skin. The adhesive can include a pad (e.g., that is locatedbetween the adhesive and the base). Additional adhesive information,including adhesive pad information, is described in U.S. patentapplication Ser. No. 14/835,603, which was filed on Aug. 25, 2015. Theentire contents of U.S. patent application Ser. No. 14/835,603 areincorporated by reference herein.

U.S. Patent Publication No. US-2013-0267811-A1; U.S. Patent ApplicationNo. 62/165,837, which was filed on May 15, 2015; and U.S. PatentApplication No. 62/244,520, which was filed on Oct. 21, 2015, includedetails regarding applicator system embodiments. The entire contents ofU.S. Patent Publication No. US-2013-0267811-A1; U.S. Patent ApplicationNo. 62/165,837; and U.S. Patent Application No. 62/244,520 areincorporated by reference herein. The entire contents of U.S. PatentPublication No. US-2009-0076360-A1 are incorporated by reference herein.

U.S. Patent Publication No. US-2011-0077490-A1, U.S. Patent PublicationNo. US-2014-0107450-A1, and U.S. Patent Publication No.US-2014-0213866-A1 describe several needle-free embodiments. The entirecontents of U.S. Patent Publication No. US-2011-0077490-A1, U.S. PatentPublication No. US-2014-0107450-A1, and U.S. Patent Publication No.US-2014-0213866-A1 are incorporated by reference herein.

The entire contents of the following application are incorporated byreference herein: U.S. patent application Ser. No. 12/893,850; filedSep. 29, 2010; and titled Transcutaneous Analyte Sensor. The entirecontents of the following application are incorporated by referenceherein: U.S. patent application Ser. No. 14/250,320; filed Apr. 10,2014; and titled Sensors for Continuous Analyte Monitoring, and RelatedMethods. The entire contents of the following application areincorporated by reference herein: U.S. patent application Ser. No.13/780,808; filed Feb. 28, 2013; and titled Sensors for ContinuousAnalyte Monitoring, and Related Methods.

As used herein, the term “base” is used very broadly, is not limited toa single component and can include many components. The base can includecomponents that move relative to each other. The base can include distaland proximal portions. A transmitter can be coupled to a proximalportion of the base, a distal portion of the base, and/or any portion ofthe base. A transmitter can be integrated into the base. A transmittercan be removably coupled to the base. The transmitter can be configuredto transmit analyte measurement data (e.g., analyte indications) to areceiver.

As used herein, “passes” is used in a manner that does not requiremovement. For example a sensor can pass through a channel without moving(e.g., by being located in the channel).

As used herein, a transcutaneous analyte measurement sensor (e.g., asensor) can include subcutaneous portions and portions that are notconfigured to enter tissue. A first segment of the sensor can be outsidethe host and a second segment of the sensor can be inside the host. Thesensor can be a transcutaneous sensor because at least a portion of thesensor can be configured to enter the host. A sensor can be a sensorassembly with many layers, conductors, insulators, membranes, andcomponents.

Some embodiments comprise one or more springs. These springs can be atorsion spring, a leaf spring, a helical spring, a conical spring, acompression spring, a tension spring, an integrally molded deformingbody, a flex arm, any suitable type of spring or combination of springs,any spring described herein, and/or any spring incorporated byreference. Some embodiments are shown with a certain type of spring,however, embodiments can be created by substituting one type of springfor another type of spring.

FIGS. 1-126 illustrate sensor systems or at least portions of sensorsystems that can be configured to measure an analyte indication. Asensor system can comprise a base having a distal side configured toface towards a skin of a host; a first adhesive coupled to the base andconfigured to couple the base to the skin; a transmitter coupled to thebase and configured to transmit analyte measurement data; and/or atranscutaneous analyte measurement sensor coupled to the base. Manyfigures focus on particular features (rather than on all featuresdescribed herein) to reduce unnecessary redundancy and to increase theclarity of descriptions related to particular features. Each feature,however, can be combined with all the other features described in thecontext of the figures included herein and/or incorporated by reference.

Sharp Protection

Measuring analyte data often involves inserting an analyte sensor intosubcutaneous tissue. Some embodiments use a needle to facilitateinserting the sensor into subcutaneous tissue. Some embodiments have asensor configured to be inserted into subcutaneous tissue without theaid of a needle. Each embodiment can be configured with or without aneedle.

Once the sensor is removed from the tissue, the sensor becomes abiohazard that has the potential to transfer viruses, bacteria, andother pathogens from the tissue to another person who is inadvertentlypierced by the sensor. Another unwanted side effect is that users canaccidently pierce themselves. Thus, in some cases it is advantageous forsystems and methods that protect people from “used” sensors (and/orneedles).

Chemical Solutions

In some embodiments, at least a portion of the sensor is configured tosoften in vivo such that the sensor is sufficiently prone to buckling atthe time the sensor is removed from the tissue that the sensor does notpose a substantial risk of accidental, unintentional piercing (becausethe sensor's column lacks sufficient strength to easily pierce skin).

A coating can be applied to the sensor. The coating can be configured tostiffen the sensor to increase a maximum buckling load of the sensor.The coating can be configured to soften and/or dissolve in response tobeing located in tissue. As a result, the coating can become so softand/or dissolve after of period of in vivo exposure that the sensor isno longer configured to pierce tissue.

In some embodiments, the wire of the sensor (and/or another portion ofthe sensor) remains sharp enough to pierce tissue after the coating hassoftened and/or dissolved, but the softening and/or dissolving of thecoating renders the sensor sufficiently prone to buckling that thesensor is no longer configured to pierce tissue. In other words, ratherthan piercing the tissue, the sensor buckles.

In some embodiments, the sharp distal end of the sensor is made of thematerial that softens and/or dissolves in vivo. As a result, the sensoris initially sharp enough to pierce the skin, but once the sharp distalend has softened and/or dissolved, the sensor is no longer configured topierce the skin. In other words, the distal end of the sensor becomesdull (e.g., less sharp) in response to in vivo exposure. Thecross-sectional surface area of the distal tip grows such that the forcerequired to pierce skin is greater than the buckling strength of thewire.

Some embodiments comprise a structure configured to support the sensoragainst buckling forces. The supporting structure can be locatedalongside the sensor. The sensor can pass through a channel of thesupporting structure. The sensor can be at least partially containedwithin a channel of the supporting structure.

The supporting structure can be tubular, C-shaped, cylindrical, and/orhave any other shape suitable to help prevent the sensor from buckling.The support structure can be made from a material that softens and/ordissolves in vivo such that the support structure becomes less rigid invivo. This change may be a result of fluid exposure to interstitialfluid (e.g., hydration) or elevated temperature.

As used herein, the term “C-shaped” is used broadly and means that astructure has an open side such that C-shapes can include U-shapes,V-shapes, and other similar shapes.

A coupling between the sensor and the support structure can be made froma material that softens and/or dissolves in vivo. As a result, thesupport structure can be configured to resist buckling when the sensoris initially inserted into tissue, but then can have lowerbuckling-resistance capabilities.

The support structure and/or the sensor can comprise a sharp tip. Thesharp tip can be configured to pierce the skin of the host.

The softening and/or dissolving material's purpose can be to add columnstrength and/or buckling resistance to the sensor to facilitateinsertion. The material can be coupled mechanically (e.g., such asconstrained in a tube) or chemically (e.g., adhesion) to the sensor.

The material can reduce accidental piercing risk via one or more of thefollowing mechanisms. The material can degrade to a state where it isunable to hold the sensor rigid enough to pierce the skin. In vivoexposure can make the secondary material no longer sharp enough (e.g.,at the distal tip) to pierce the skin. The material can soften and/ordissolve such that the sensor and the support structure uncouple and/orthe support structure is no longer configured to hold the sensor in arigid and/or approximately straight state.

The following application, the entire contents of which are incorporatedby reference herein, includes information regarding softening anddissolving materials: U.S. patent application Ser. No. 14/250,320; filedApr. 10, 2014; and titled Sensors for Continuous Analyte Monitoring, andRelated Methods.

The coating material and/or the support structure material can be abiodegradable material and/or a material that dissolves upon insertioninto the host. Example materials include at least one of a salt, ametallic salt, a sugar, a synthetic polymer, a glue or adhesive (such ascyanoacrylate), polylactic acid (PLA), polyglycolic acid, polylactic-co-glycolic acid (PLGA), a polyanhydride, a polyphosphazene, orany material with a glass transition temperature of 37 plus or minus 10degrees Celsius.

FIG. 2 illustrates a perspective view of a sensor system 202 a. FIG. 3illustrates a cross-sectional view along line 3-3 from FIG. 2. Referringnow to FIG. 3, the sensor 206 a can comprise a section located distallyrelative to the base 204 a. The section of the sensor 206 a can comprisea first portion 255 and a second portion 256. The first portion 255 ofthe sensor 206 a can be configured to facilitate maintaining the secondportion 256 in a straight configuration during insertion of the sectioninto the skin. The first portion 255 of the sensor 206 a can beconfigured to soften in response to being located in vivo.

The first portion 255 can comprise a first buckling resistance prior tothe insertion and a second buckling resistance after one hour, 12 hours,and/or 48 hours of being located in vivo. The second buckling resistancecan be less than the first buckling resistance. The second bucklingresistance can be at least 30 percent less and/or at least 70 percentless than the first buckling resistance.

FIG. 126 illustrates a cross-sectional view along line 126-126 from FIG.116. Any of the sensors described herein and/or incorporated byreference can include the features described in the context of FIG. 126.The features described in the context of FIG. 126 are not described inthe context of each sensor embodiment to avoid unnecessary redundancy.

FIG. 126 illustrates an embodiment in which a portion (e.g., 692 c, 683a, 691 a, 690 a, a sensor core, a sensor layer, a sensor supportstructure) of the sensor 616 is configured to soften in vivo. Thisportion can soften sufficiently in vivo that at the time the sensor 616is removed from the tissue of the host, the sensor 616 is sufficientlyprone to buckling that the sensor 616 does not pose a substantial riskof piercing another person.

The sensor 616 can comprise a first conductive layer 690 a (e.g.,platinum), a first insulation layer 692 c (e.g., a polyurethanecoating), and a second conductive layer 691 a (e.g., a silver/silverchloride coating). The first insulation layer 692 c can block directelectrical conductibility between the first conductive layer 690 a andthe second conductive layer 691 a (e.g., such that the first conductivelayer 690 a and the second conductive layer 691 a are electricallycoupled only by tissue and/or fluid of the host as explained in thecontext of FIG. 125). The sensor 616 can comprise an outer membrane 683a.

The insulation layer 692 a can be formulated to soften in response tobeing located in vivo. The softening of the insulation layer 692 a(and/or any other portion of the sensor 616) makes the sensor 616 moreprone to buckling, and thus, less prone to mistakenly piercing the skin(e.g., of the wrong person).

Sliding Arms

Once the sensor is removed from the tissue, the sensor can inadvertentlypierce the skin of another person. Some embodiments overcome thispotential hazard by retracting at least a portion of the sensor (e.g.,as the sensor is removed from the skin and/or after the sensor isremoved from the skin). Some embodiments cover the distal portion of thesensor to shield the sensor from piercing a person after the sensor isremoved.

Several embodiments comprise an arm that is slidably coupled to thebase. The arm can be configured to retract a distal portion of thesensor and/or cover the distal portion of the sensor.

Horizontal Pull Tab

One way to preclude a “used” sensor from inadvertently piercing the skinof a person is to retract the sensor (e.g., into an interior cavity ofthe system). The system (e.g., the wearable and/or the applicator) caninclude a portion configured to slide approximately parallel to theskin. Sliding the portion can retract the sensor. The portion thatslides can be a pull tab and/or the transmitter. For example, pullingthe pull tab and/or removing the transmitter can cause the system toretract the sensor.

FIGS. 2-4 illustrate a sensor system 202 a that includes an arm 203slidably coupled to a base 204 a. Sliding the arm 203 in the directionshown by arrow 205 can retract the sensor 206 a to prevent the sensor206 a from piercing a person.

FIG. 2 illustrates a perspective view of the sensor system 202 a. FIG. 3illustrates a cross-sectional view along line 3-3 from FIG. 2. FIG. 4also illustrates a cross-sectional view like FIG. 3 except that the arm203 has been moved in the direction shown by arrow 205 in FIG. 2 toretract the sensor 206 a.

Referring now to FIGS. 2-4, some embodiments comprise a sensor system202 a for measuring an analyte concentration. The sensor system 202 acan comprise a base 204 a having a distal side 207 a configured to facetowards a skin of a host. FIGS. 3 and 4 illustrate a proximal direction208 (e.g., away from the skin) and a distal direction 209 (e.g., towardsthe skin).

The sensor system 202 a can comprise a first adhesive 210 coupled to thebase 204 a and configured to couple the base 204 a to the skin; atransmitter 211 a coupled to the base 204 a and configured to transmitanalyte measurement data; and/or a transcutaneous analyte measurementsensor 206 a coupled to the base 204 a.

The system can comprise a pull tab system 213 that includes a pull tab214. The pull tab system 213 can be configured to retract the sensor 206a in response to moving the pull tab 214 relative to the base 204 a.

The pull tab system 213 can comprise a channel 215 and an intermediateportion 216 that couples the channel 215 to the pull tab 214. The pulltab 214 can protrude away from the base 204 a. A first portion of thesensor 206 a can pass through the channel 215. The pull tab system 213can be configured such that pulling the pull tab 214 moves the channel215 to retract the sensor 206 a.

The channel 215 can be formed by a hole, a slot, and/or a hook. Thechannel 215 can be formed by a wall configured to push and/or pull thesensor 206 a. The channel 215 can be open on one side to facilitateassembling the system (by enabling the sensor 206 a to be inserted intothe channel 215 through the open side).

The base 204 a can comprise a channel (e.g., a second hole 219). Asecond portion of the sensor 206 a can pass through the second hole 219.The pull tab system 213 can be configured such that pulling the pull tabretracts the sensor 206 a by pulling the second portion of the sensor206 a out of the second hole 219 and into an interior area 220 of thesensor system 202 a.

The pull tab system 213 can be slidably coupled to the base 204 a suchthat the pull tab system 213 is configured to slide in a first direction205 that is within 20 degrees (e.g., within plus or minus 20 degrees)and/or within 45 degrees (e.g., within plus or minus 45 degrees) ofbeing perpendicular to a proximal direction 208 oriented away from theskin. (The pull tab system 213 can be configured to slide in a direction205 that is within plus or minus 20 degrees and/or within plus or minus45 degrees of being perpendicular to a distal direction 209 orientedtowards the skin.)

The transmitter 211 a can be slidably coupled to the base 204 a suchthat the transmitter 211 a is configured to slide in a second direction221 that is within plus or minus 20 degrees and/or within plus or minus45 degrees of being perpendicular to the proximal direction 208. Thesecond direction 221 can be within plus or minus 20 degrees and/orwithin plus or minus 45 degrees of being parallel to the first direction205. (In some embodiments, the transmitter is coupled to the base by theuser or permanent attachment to the base in the factory.)

Horizontal Push Tab or Button

The embodiment illustrated in FIGS. 5-7 is also configured to retractthe sensor 206 b to prevent the sensor 206 b from piercing the skin(e.g., after the sensor 206 b has been removed from the host).

Rather than use a pull tab, the embodiment illustrated in FIGS. 5-7includes a button 222, which can be a push tab or an electronic button.The system 202 b can be configured such that pressing a button 222(e.g., a push tab) into an outer housing causes the sensor 206 b toretract into the outer housing. Thus, the system 202 b precludes a“used” sensor 206 b from inadvertently piercing the skin of a person byretracting the sensor 206 b (e.g., into an interior cavity of the system202 b).

FIG. 5 illustrates a perspective view of the system 202 b. FIG. 6illustrates a cross-sectional view along line 6-6 from FIG. 5. FIG. 6illustrates the sensor 206 b prior to being retracted into an interiorarea of the sensor system 202 b. FIG. 7 illustrates the samecross-sectional view as shown in FIG. 6 except that the sensor 206 b hasbeen retracted into the system 202 b.

Referring now to FIGS. 5-7, the system 202 b can comprise a push buttonsystem having a push button 222. The push button system can beconfigured to retract the sensor 206 b in response to pushing the button222 (e.g., in the direction shown by the arrow 223 in FIG. 5). In someembodiments, the button 222 is electrically activated rather thanmechanically activated.

At least a portion 225 of the push button system can protrude away fromthe base 204 b. The push button system can be configured such thatpressing the portion 225 of the push button system into the base 204 bengages a sensor retraction hoop or hook 226 that pulls and/or pushesthe sensor 206 b into an interior area of the sensor system 202 b.

The push button system can further comprise a channel 227 and anintermediate portion 228 that couples the channel 227 to the push button222. The push button 222 can protrude away from the base 204 b. A firstportion of the sensor 206 b can pass through the channel 227. The pushbutton system can be configured such that pushing the button 222 movesthe channel 227 to retract the sensor 206 b.

The channel 227 can be formed by a hole, a slot, and/or a hook 226. Thechannel 227 can be formed by a wall configured to push and/or pull thesensor 206 b. The channel 227 can be open on one side to facilitateassembling the system 202 b (by enabling the sensor 206 b to be insertedinto the channel 227 through the open side).

The base 204 b can comprise a second channel formed by a second hole229. A second portion of the sensor 206 b can pass through the secondhole 229. The push button system can be configured such that pushing thebutton 222 retracts the sensor 206 b by pulling the second portion ofthe sensor 206 b out of the second hole 229 and into an interior area ofthe sensor system 202 b by making a third portion of the sensor 206 bform a U-shape and/or a torturous shape.

The push button system can be slidably coupled to the base 204 b suchthat the push button system is configured to slide in a first direction223 that is within plus or minus 20 degrees and/or within plus or minus45 degrees of being perpendicular to a proximal direction oriented awayfrom the distal side of the base 204 b. (The proximal direction isopposite relative to the distal direction 209.)

The push button system can comprise a first arm (e.g., a portion thatincludes the channel 227) and an intermediate portion 228 that couplesthe first arm to the push button 222. The push button 222 can protrudeaway from the base 204 b. A first portion of the sensor 206 b can passthrough a channel 227 of the first arm (e.g., as illustrated in FIG. 6).The push button system can be configured such that pushing the buttonmoves the first arm to retract the sensor 206 b (e.g., as illustrated inFIG. 7).

The transmitter 211 b can be slidably coupled to the base 204 b suchthat the transmitter 211 b is configured to slide in a second direction230 that is within plus or minus 20 degrees and/or within plus or minus45 degrees of being perpendicular to the proximal direction. The seconddirection 230 can be within plus or minus 20 degrees and/or within plusor minus 45 degrees of being parallel to the first direction 223.

In some embodiments, a first adhesive 210 that couples the system 202 bto the skin can have a tab 231 configured to help a person peel thefirst adhesive 210 off the skin. This adhesive removal tab 231 can be atleast partially covered by the push tab 222 to encourage the user topress the push tab 222 into the outer housing before using the adhesiveremoval tab 231 to peel the first adhesive 210 off the skin.

Trigger—Sliding Arm

Several embodiments automatically retract the sensor into an interiorarea of the system. For example, uncoupling the system from the skin cancause the sensor to retract automatically. Automatic retraction isadvantageous because it does not rely on a person remembering to performextra steps. For example, the system can retract the sensor in responseto a person uncoupling at least a portion of a system from the skin.

Embodiments can comprise a trigger. Activating the trigger can cause thesensor to retract (e.g., into an interior cavity of the system).

The trigger can be spring-loaded such that uncoupling the base from theskin moves and/or removes a pin to release a compressed spring and/or anextended spring (e.g., a stretched spring). The spring can be in ahigh-energy state such that the system is configured to release a forceof the spring in response to moving the pin. The spring can be any typeof spring described herein and/or incorporated by reference. The springcan be a leaf spring, a flex arm (e.g., an integrally molded flex arm),a conical spring, and/or any suitable type of spring and/or combinationof multiple springs.

Releasing the spring can cause the spring force to retract the sensorinto an interior area of the system. The movement caused by releasingthe spring can cause a pushing action and/or a pulling action to retractthe sensor.

The system can have a first adhesive to couple the base to the skin. Thesystem can also have a second adhesive that couples the release pin tothe skin. As a result, uncoupling the base from the skin can pull therelease pin out of the base and/or at least partially away from the base(as the release pin continues to be adhered to the skin). In someembodiments, the first and second adhesives may be on the same body.

In some embodiments, the pin can be configured to remain coupled to thebase even after the base is uncoupled from the skin. For example, thepin can be configured to telescope a limited distance and be retained byan undercut feature. Thus, the post can remain attached to the basewhile moving to a position that releases the spring.

FIG. 8 illustrates a perspective view of an embodiment with aspring-loaded arm 233 that is configured to retract the sensor 206 c inresponse to releasing the arm 233. A release mechanism (e.g., a pin 235)can be used to hold the arm 233 in a starting position prior to the arm233 retracting the sensor 206 c. FIG. 9 illustrates a cross-sectionalview from the perspective shown in FIG. 8. In FIG. 9, the arm 233 is ina high-energy state (due to the energy stored in the spring 234). Movingthe pin 235 releases the spring 234 to drive the arm 233 to retract thesensor 206 c (as shown in FIG. 10).

Referring now to FIGS. 8-10, some embodiments comprise a spring-loadedarm 233 slidably coupled to the base 204 c such that removing the sensorsystem 202 c from the skin causes the sensor 206 c to automaticallyretract in response to the arm 233 sliding relative to the base 204 c.

The base 204 c can be configured to face towards the skin in a firstdirection 209 (e.g., a distal direction). The arm 233 can be configuredto slide in a second direction 237 that is within plus or minus 20degrees and/or within plus or minus 45 degrees of perpendicular to thefirst direction 209. At least a portion of the sensor 206 c can passthrough a portion 238 of the arm 233 such that moving the arm 233 in thesecond direction 237 causes the portion 238 of the arm 233 to retractthe sensor 206 c into an interior area 239 (e.g., a cavity) of thesensor system 202 c.

Several embodiments comprise a spring 234 and a release pin 235. Thespring 234 can be in at least one of a compressed state and an extendedstate (e.g., a stretched state) such that removing the release pin 235causes the spring 234 to move at least a first portion of the sensor 206c into the base 204 c.

Some embodiments comprise an arm 233 slidably coupled to the base 204 c.The arm 233 can comprise a first channel 238 (e.g., formed by a hole, aslot, and/or a hook). The first channel 238 can be aligned with a secondchannel 242 (e.g., a second hole) of the base 204 c such that a secondportion of the sensor 206 c passes through the first channel 238 and thesecond hole. The spring 234 can be at least one of compressed andextended (e.g., stretched) between a first wall of the base 204 c and asecond wall of the arm 233. The release pin 235 can pass through a thirdchannel 243 (e.g., a third hole) of the base 204 c and can interferewith a portion of the arm 233 to prevent the spring 234 from moving thearm 233 to retract the sensor 206 c.

The release pin 235 can comprise a distal face having a second adhesive240 configured to be applied to the skin such that removing the base 204c from the skin uncouples the first adhesive from the skin but does notuncouple the second adhesive 240 from the skin, which causes the releasepin 235 to be removed from the third hole, and thereby enables thespring 234 to move the arm 233 to retract the sensor 206 c. In someembodiments, the pin 235 moves relative to the base 204 c, but remainscoupled to the base 204 c after the pin 235 releases the arm 233 toretract the sensor 206 c into the system 202 c.

The spring 234 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

A transmitter 211 c can be removably coupled to the base 204 c and/orintegrated into the base 204 c. The base 204 c can comprise a battery430 configured to provide electrical power to the sensor 206 c and/orthe transmitter 211 c.

Trigger—External Arm

Several embodiments include a spring-loaded arm that is configured tobend and deflect a distal portion of the sensor. As a result, thespring-loaded arm can prevent the sensor from piercing the skin of aperson.

The arm can slide approximately perpendicularly to a distal direction(rather than approximately parallel to a distal direction as used insome embodiments). The sliding arm can be located at least partiallyoutside of the housing of the system.

Activating a trigger can cause the system to bend and deflect a distalportion of the sensor such that the distal portion can no longer piercethe skin. The distal portion of the sensor can be held between a slidingarm (that is activated by a triggering mechanism) and the base. Adhesivecan secure the trigger in a starting position such that uncoupling theadhesive from the skin activates the trigger to bend the distal portionof the sensor.

FIG. 11 illustrates a perspective view of an embodiment with aspring-loaded arm 248 that is configured to bend a portion of the sensor206 d against the distal side 207 d of the base 204 d to prevent thesensor 206 d from inadvertently piercing a person after the sensor 206 dis removed from the tissue of a host. FIG. 12 illustrates across-sectional, perspective view of the embodiment shown in FIG. 11. InFIG. 12, the arm 248 has not yet bent the sensor 206 d. For example, thesensor configuration illustrated in FIG. 12 can be when the sensor 206 dis at least partially located in tissue of the host. FIG. 13 illustratesa cross-sectional, perspective view of the embodiment shown in FIG. 11except that the arm 248 has moved relative to the base 204 d to bend thesensor 206 d. In FIG. 13, the transmitter 211 d has been uncoupled fromthe base 204 d.

Referring now to FIGS. 11-13, some embodiments comprise a spring-loadedarm 248 slidably coupled to the base 204 d and configured such thatremoving the sensor system 202 d from the skin causes the arm 248 tocollide with a first portion of the sensor 206 d and bend the sensor 206d such that a second portion of the sensor 206 d is located between thearm 248 and the base 204 d (e.g., as shown in FIG. 13).

The base 204 d can be configured to face towards the skin in a firstdirection 209 (e.g., a distal direction). The sensor system 202 d cancomprise a spring 234 d oriented within plus or minus 20 degrees and/orwithin plus or minus 45 degrees of perpendicular to the first direction209. The spring 234 d can be located in an interior area of the sensorsystem 202 d and can be configured to cause the arm 248 to collide withthe first portion of the sensor 206 d.

The spring 234 d can be a torsion spring, a leaf spring, a helicalspring, a conical spring, a compression spring, a tension spring, anintegrally molded deforming body, a flex arm, any type of springdescribed herein, any type of spring incorporated by reference, and/orany suitable type of spring.

The base 204 d can be configured to face towards the skin in a firstdirection 209. The arm 248 can be configured to slide in a seconddirection 249 that is within plus or minus 20 degrees of perpendicularto the first direction 209 such that the second portion of the sensor206 d is oriented within plus or minus 20 degrees of perpendicular tothe first direction 209.

The sensor 206 d can pass through a channel 251 (e.g., a hole) of thebase 204 d. The first portion of the sensor 206 d can be locateddistally relative to the hole of the base 204 d. The arm 248 can bespring-loaded towards the first portion of the sensor 206 d. The arm 248can comprise a protrusion 252 that protrudes towards the first portionof the sensor 206 d such that sliding the arm 248 causes the protrusion252 to collide with the first portion of the sensor 206 d and positionsthe protrusion 252 directly distally relative to the channel 251 (e.g.,the hole) of the base 204 d.

The protrusion of the arm 248 can comprise a second adhesive 253configured to couple the arm 248 to the skin such that the secondadhesive 253 holds the arm 248 in a first position in which the arm 248does not bend the sensor 206 d. Uncoupling the second adhesive 253 fromthe skin can cause the arm 248 to the bend the sensor 206 d such thatthe second portion of the sensor 206 d is located between the arm 248and the base 204 d.

Rotating Arms

Several embodiments comprise an arm that is rotatably coupled to thebase. The rotating arm can prevent a sensor (and/or a needle) fromposing a risk of piercing the skin.

The rotating arm can be configured to retract a distal portion of thesensor and/or cover the distal portion of the sensor to shield thesensor from inadvertently piercing a person. The rotating arm can bemanually triggered or automatically triggered. In some embodiments, thearm automatically rotates in response to uncoupling the base from theskin.

Spring Flap

Some embodiments include an arm that is rotatably coupled to the basesuch that uncoupling the system from the skin releases the arm such thatthe arm rotates towards a distal portion of the sensor. The arm can bendthe sensor and/or trap a distal portion of the sensor between the armand the base to preclude the sensor from piercing skin unintentionally.

The arm can be driven (e.g., pushed directly or indirectly, pulleddirectly or indirectly) by a spring configured to rotate the arm towardsa distal portion of the sensor. The spring can be a torsion spring, aleaf spring, a helical spring, a conical spring, a compression spring, atension spring, an integrally molded deforming body, a flex arm, anytype of spring described herein, any type of spring incorporated byreference, and/or any suitable type of spring.

The system can have a first state in which the skin interferes withrotation of the arm. Once the system is uncoupled from the skin, the armcan be free to rotate to bend the sensor. For example, once the skinand/or a locking mechanism no longer constrains the spring, the springforce can cause the arm to rotate.

FIG. 14 illustrates a perspective view of a system 202 e with an arm 260rotatably coupled to a base 204 e by a hinge 261. FIG. 15 illustrates aside, cross-sectional view of the system 202 e shown in FIG. 14. Thetransmitter 211 e is hidden in FIGS. 14 and 15 to facilitate clearlyviewing the rotating arm 260. The optionally removable transmitter 211 eis shown in FIG. 16. FIG. 16 illustrates a perspective view of thesystem 202 e.

Referring now to FIGS. 14-16, the arm 260 can be spring loaded such thatthe arm 260 is configured to rotate in the direction shown by arrow 265about the hinge 261. FIG. 15 illustrates a portion 264 of the sensor 206e. The portion 264 is located distally relative to the distal side 207e. At least a section of this portion 264 can be bent and/or deflectedby the rotation of the arm 260 such that the section is located betweenthe arm 260 and the distal side 207 e (e.g., as shown in FIG. 16).

The arm 260 can have a starting position in which the arm 260 is locatedin a recession of the base 204 e (e.g., as shown in FIGS. 14 and 15).The arm 260 can have an ending position in which the arm 260 shields thesensor 206 e from penetrating skin (e.g., as shown in FIG. 16).

The hinge 261 can be configured such that uncoupling the base 204 e fromthe skin causes the hinge 261 to rotate such that the arm 260 bends atleast a first portion of the sensor 206 e and covers at least a secondportion of the sensor 206 e.

The system 202 e can comprise a torsional spring 262 coupled to the arm260 such that the torsional spring 262 biases the arm 260 in arotational direction 265 towards the second portion of the sensor 206 e.

The hinge 261 can be located in an interior area of the sensor system202 e (as shown in FIGS. 14 and 15). The arm 260 can comprise a portionconfigured to cover the second portion of the sensor 206 e. The sensorsystem 202 e can comprise a first state in which the portion of the arm260 is located in the interior area (as shown in FIGS. 14 and 15). Thetransmitter 211 e is hidden in FIGS. 14 and 15, but the portion of thearm 260 is located in the interior area in FIGS. 14 and 15. The sensorsystem 202 e can comprise a second state in which the portion of the arm260 is located distally relative to the base 204 e (as shown in FIG.16).

Pivoting System

In some embodiments, a hinge is used to retract the sensor to shield thesensor from piercing skin. The movement of the hinge can pull the sensorout of the tissue of the host and into an area between a first part ofthe system and a second part of the system.

The system can comprise a lift tab configured to enable a user to easilymove a proximal portion of the system to cause the hinge to rotate. Thisrotation can pivot the proximal portion relative to the distal portionof the system to retract the sensor.

FIG. 17 illustrates a perspective view of a system 202 f that includes ahinge 270 configured to retract the sensor 206 f. FIG. 18 illustrates aside, cross-sectional view of the system 202 f in a state prior tosensor retraction. FIG. 19 illustrates a side, cross-sectional view ofthe system 202 f in a state after sensor retraction.

Referring now to FIGS. 17-19, some systems 202 f comprise a firstportion 272 coupled to a second portion 273 by a hinge 270. Pivoting thefirst portion 272 relative to the second portion 273 can retract thesensor 206 f to preclude the sensor 206 f from piercing the skin ofanother person. The second portion 273 can be coupled to the firstportion 272 by a hinge 270 configured such that increasing a pivot angle271 between the first portion 272 and the second portion 273 retractsthe sensor 206 f.

The sensor system 202 f can comprise a base 204 f, a transmitter 211 f,and a distal side 207 f. A spring 275 (e.g., a helical spring, acompression spring, a tension spring, a leaf spring, a torsional spring)can be configured to increase the pivot angle 271 (e.g., once releasedby a triggering mechanism and/or any suitable mechanism).

The spring 275 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

The hinge 270 can comprise a pin 276 rotatably coupled to a sleeve 277configured to retain the pin 276 as the second portion 273 rotatesrelative to the first portion 272. As used herein, the term “sleeve” isused broadly and can mean a tubular part, a hollow axle, and/or abushing designed to fit over another part to retain the other partduring pivoting. Sleeve can be an open-ended flat or tubular packagingor cover. Some sleeves are not cylindrical or full cylinders (e.g.,sleeves can have a slot).

The base 204 f can comprise the first portion 272 and the second portion273. The first portion 272 can couple the first adhesive 210 to thesecond portion 273.

The base 204 f can comprise the first portion 272. The second portion273 can comprise the transmitter 211 f.

A distal portion of the sensor 206 f can pass through a channel 278(e.g., a hole) of the base 204 f. A proximal portion of the sensor 206 fcan be coupled to the second portion 273 such that increasing the pivotangle 271 retracts the distal portion of the sensor 206 f through thechannel 278 of the base 204 f and into an area between the first portion272 and the second portion 273 of the sensor system 202 f.

The base 204 f can comprise a left half 279 and a right half 280. Theleft half 279 can comprise the channel 278 of the base 204 f. The righthalf 280 can comprise at least a portion of the hinge 270.

The second portion 273 can comprise a lift tab 281 configured to enablea user to grip a distally facing surface 282 to rotate the secondportion 273 relative to the first portion 272. The lift tab 281 cancomprise a protrusion that protrudes away from the hinge 270. The lifttab may be coupled to a flex arm that releasably couples the first andsecond portions. Applying force to the lift tab may activate thedecoupling.

Hinged Baseplate

In some embodiments, the system comprises a hinged base configured tofold over the sensor to preclude the sensor from piercing anotherperson. The user can fold one side of the base over the sensor. A springcan move one side of the base over the sensor.

FIG. 20 illustrates a perspective view of a base 204 g that comprises afirst portion 294 and a second portion 295. The first portion 294 of thebase 204 g is configured to rotate relative to the second portion of thebase 204 g to shield a distal portion of the sensor 206 g to prevent thesensor 206 g from piercing a person. The first portion 294 can rotateabout a hinge 297 in a direction indicated by arrow 291 in FIG. 20.

FIG. 21 illustrates a perspective view of the base 204 g after the firstportion 294 has rotated approximately 90 degrees relative to the secondportion 295. The first portion 294 can continue rotating in thedirection indicated by arrow 292 to arrive at the state illustrated inFIGS. 22a and 22 b.

FIG. 22a illustrates a top view of the system 202 g. FIG. 22billustrates a side view of the system 202 g. In FIGS. 22a and 22b , thesensor 206 g is shielded from piercing skin by the first portion 294 ofthe base 204 g.

Referring now to FIGS. 20-22 b, the base 204 g can comprise a firstportion 294 and a second portion 295. The second portion 295 of the base204 g can be coupled to the first portion 294 of the base 204 g by ahinge 297 configured such that decreasing a pivot angle between thefirst portion 294 and the second portion 295 of the base 204 g places aportion of the sensor 206 g between the first portion 294 and the secondportion 294 of the base 204 g. A transmitter 211 g can be coupled to thebase 204 g.

The hinge 297 can comprise a first pin rotatably coupled to a first holeconfigured to retain the first pin as the first portion 294 of the base204 g rotates relative to the second portion 295 of the base 204 g.

The hinge 297 can comprise a second pin rotatably coupled to a secondhole configured to retain the second pin as the first portion 294 of thebase 204 g rotates relative to the second portion 295 of the base 204 g.The first pin can protrude in a first direction. The second pin canprotrude in a second direction that is opposite relative to the firstdirection.

The first adhesive can comprise a first section 290 b and a secondsection 290 a coupled to a distal side 207 g of the base 204 g. Thefirst section 290 b can be coupled to the first portion 294 of the base204 g such that the first section 290 b is configured to adhere thefirst portion 294 of the base 204 g to the skin. The second section 290a can be coupled to the second portion 295 of the base 204 g such thatthe second section 290 a is configured to adhere the second portion 295of the base 204 g to the skin. The hinge 297 can be configured to enablethe first section 290 b of the first adhesive to face towards the secondsection 290 a of the first adhesive while the portion of the sensor 206g is at least partially confined between the first portion 294 and thesecond portion 295 of the base 204 g.

The system 202 g can be configured to bend the portion of the sensor 206g in response to rotating the hinge 297. The portion of the sensor 206 gcan be bent between the first portion 294 and the second portion 295 ofthe base 204 g to guard against a distal tip of the sensor 206 gpenetrating tissue after the sensor system 202 g is removed from theskin.

The first portion 294 of the base 204 g can be rotationallyspring-loaded relative to the second portion 295 of the base 204 g suchthat the system 202 g is configured to decrease the pivot angle inresponse to a rotational spring bias.

The system 202 g can comprise a torsion spring 298 coupled to the hinge297 such that the torsion spring 298 is configured to decrease the pivotangle to place the portion of the sensor 206 g between the first portion294 and the second portion 295 of the base 204 g.

The spring 298 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

Patch Folds Over Sensor

One way to prevent the sensor from being a hazard is to fold a portionof the adhesive over the sensor. For example, the adhesive can have alarger footprint that is typically used to couple the base to the skin.A portion of the larger footprint can be folded over the sensor.

In some embodiments, the system can comprise a compliant, pliable sheetconfigured to fold over the sensor after the sensor is removed from thetissue. Prior to being used to shield the sensor, the sheet can befolded in a compact manner. Deploying the sheet over the sensor caninclude unfolding the sheet.

The sheet can include a puncture-resistant material such as a foil. Thisway, the sheet can be very easy to fold while the puncture-resistantmaterial can be optimized to prevent the sensor's distal tip frompiercing the puncture-resistant material.

In some embodiments, the sheet has a puncture resistance that blocks thesensor from puncturing the sheet during normal operating conditions. Asa result, an additional puncture-resistant material is not necessary.

FIG. 23 illustrates a perspective view of a sensor system 202 h thatincludes a pliable sheet 300 configured to cover a distal tip of thesensor 206 h. FIG. 24 illustrates another perspective view of the system202 h in a state when the pliable sheet 300 is folded in a storageposition. FIG. 25 illustrates a perspective view of the pliable sheet300 as the pliable sheet 300 is unfolded. The pliable sheet 300continues to move towards the distal tip of the sensor 206 h until thepliable sheet 300 arrives at the state shown in the side viewillustrated in FIG. 26. Then, the pliable sheet 300 can continue movingtowards the distal tip of the sensor 206 h until the pliable sheet 300covers the distal tip of the sensor 206 h (as illustrated in theperspective view shown in FIG. 27).

Referring now to FIGS. 23-27, the system 202 h can comprise an adhesiveportion of the sheet 300 configured to bend at least a portion of thesensor 206 h towards the base 204 h. A distal tip of the sensor 206 hcan be located between the base 204 h and the adhesive portion. Atransmitter 211 h can be coupled to the base 204 h.

The system 202 h can comprise a pliable sheet 300 that covers a distaltip of the sensor 206 h and adheres to the first adhesive 210 h suchthat the pliable sheet 300 guards against the distal tip of the sensor206 h penetrating tissue after the sensor system 202 h is removed fromthe skin. The pliable sheet 300 can be coupled to the distal side 207 hof the base 204 h (e.g., as shown in FIG. 27).

The first adhesive 210 h can couple the pliable sheet 300 to the base204 h. The pliable sheet 300 can comprise a first state in which thepliable sheet 300 is folded, is located proximally relative to thedistal tip, does not cover the distal tip, and forms a tab configured toenable a user to unfold the pliable sheet 300 (e.g., as shown in FIGS.23 and 24).

The pliable sheet 300 can comprise a second state in which the pliablesheet 300 is at least partially unfolded relative to the first state, isat least partially located distally relative to the distal tip, and thedistal tip of the sensor 206 h is at least partially confined betweenthe pliable sheet 300 and the first adhesive 210 h (e.g., as shown inFIG. 27).

The system 202 h can comprise a second sheet 301 having a secondpuncture resistance that is greater than a first puncture resistance ofthe pliable sheet 300. The second sheet 301 can be located between thedistal tip and the pliable sheet 300 to protect the pliable sheet 300from being punctured by the distal tip. The second sheet 301 can becoupled to the pliable sheet 300 such that the second sheet 301 deformsthe distal tip as the pliable sheet 300 is folded over the distal tip.

A distal tip of the sensor 206 h can be at least partially confinedbetween a pliable sheet 300 and the base 204 h such that the pliablesheet 300 holds at least a portion of the sensor 206 h in a bentposition and the pliable sheet 300 is adhered to the first adhesive 210h.

The pliable sheet 300 can comprise a first state and a second state. Inthe first state, the pliable sheet 300 can be located proximallyrelative to the first adhesive 210 h when the sensor system 202 h iscoupled to the skin. In the second state, the pliable sheet 300 can belocated distally relative to the first adhesive 210 h when the distaltip of the sensor 206 h is at least partially confined between thepliable sheet 300 and the base 204 h. As used herein, the term “pliable”means able to at least one of be bent and be folded. The sheet can alsobe compliant.

Protective Slot to Hold Sensor

A distal side of the base can include a slot configured to hold a distalend of the sensor after the sensor is removed from the tissue. Thedistal end of the sensor can be manually pressed into the slot.

The sensor can permanently deform to hold the distal end of the sensorin the slot. Once the distal end of the sensor is located in the slot,the sensor is precluded from piercing another person. In someembodiments, the sensor elastically deforms to at least partially enterthe slot.

Referring now to FIG. 24, a distal side 207 h of the base 204 h cancomprise a slot 302 configured to receive a distal end of the sensor 206h after the sensor 206 h is removed from the host. A first portion ofthe sensor 206 h can be bent and/or deflected such that the distal endof the sensor 206 h is located in the slot 302. Once the sensor 206 h isbent, the distal end of the sensor 206 h can be located proximallyrelative to the first adhesive 210 h.

The base 204 h (labeled in FIG. 23) can comprise a channel 303 (e.g., ahole). A second portion of the sensor 206 h can pass through the channel303. The slot 302 can be directly coupled to the channel 303 (e.g., suchthat the channel 303 and the slot 302 are in fluid communication). Theslot 302 can be oriented within plus or minus twenty degrees ofperpendicular a central axis of the channel 303.

Spinning Retraction

There are many ways to retract a sensor to prevent the sensor frompiercing the skin. In some embodiments, a portion of the system canrotate (relative to the base) to retract (e.g., “wind in”) the sensorinto an interior cavity of the system.

The portion that rotates can comprise the transmitter. The portion thatrotates can be a spinning dial, which can be located radially inward oroutward relative to a portion of the base that couples the rotatingportion to the first adhesive. The rotating portion can include tractionfeatures (e.g., a divot, a protrusion, a rough surface finish) to enableusers to grip the rotating portion.

FIG. 28 illustrates a top view of a system 202 i configured to “wind up”a sensor 206 i. FIG. 29 illustrates a perspective view of the system 206i. In FIG. 29, the sensor is deployed (e.g., extends distally from thedistal side 207 i, located in tissue of the host). FIG. 30 illustrates aperspective view of the system 206 i after the sensor 206 i has beenretracted into the housing.

Referring now to FIGS. 28-30, the sensor system 202 i can comprise afirst portion 310 and a second portion 311. The first portion 310 cancouple the first adhesive 210 i to the second portion 311. The secondportion 311 can be rotatably coupled to the first portion 310 about anaxis of rotation that is within plus or minus twenty degrees of beingparallel to a proximal direction such that the sensor system 202 i isconfigured to retract the sensor 206 i in response to rotating thesecond portion 311 relative to the first portion 310. The base 204 i cancomprise the first portion 310. The second portion 311 can comprise thetransmitter 211 i. The sensor 206 i can exit a distal side 207 i of thebase 204 i.

The system 202 i can comprise an interior area 312 between the firstportion 310 and the second portion 311. The interior area 312 can beconfigured such that spinning the second portion 311 relative to thefirst portion 310 moves the interior area 312 relative to at least oneof the first portion 310 and the second portion 311. The interior area312 can be configured such that spinning the second portion 311 relativeto the first portion 310 retracts at least a portion of the sensor 206 ithrough a channel 313 (e.g., a hole) in the base 204 i and into theinterior area 312.

The base 204 i can comprise a distally facing hole 313. The sensor 206 ican comprise a proximal portion coupled to the second portion 311 and adistal portion that passes through the hole 313 in the base 204 i (e.g.,as shown in FIG. 29).

The system 202 i can comprise a proximally facing indentation 314configured to provide traction for a user to rotate the second portion311 relative to the first portion 310.

The system 202 i can comprise a proximal protrusion 315 configured toprovide traction for a user to rotate the second portion 311 relative tothe first portion 310.

Sensor Covers

One way to preclude the sensor from inadvertently piercing tissue is tocover the sensor (e.g., before or after use). The system can comprise acover coupled to the base such that a distal tip of the sensor islocated between the cover and the distal side of the base. Sensor coverscan have many different shapes. A cover can be coupled to the base suchthat a distal tip of the sensor is located in an interior area of thecover.

A cover (e.g., a shroud) can be coupled to the distal side of the base.Once the sensor is removed from the tissue, the cover can be manuallyunrolled over the sensor. In some embodiments, the relaxed state of thecover is the unrolled state such that the cover automatically unrollsonce the tissue (or a part of the system) is no longer blocking thecover from unrolling. The cover can be a shroud configured to cover aportion of the sensor.

FIGS. 31 and 32 illustrate a side view of a system 202 j that comprisesan extendable sensor cover 318. The system 202 j can comprise atransmitter 211 j and a base 204 j. The base 204 j can comprise a distalside 207 j that has adhesive 210 configured to couple the base 204 j tothe skin of a host.

The extendable cover 318 has a contracted state (e.g., a retracted stateas shown in FIG. 31) configured to enable a distal end of the sensor 206j to enter the host. The extendable cover 318 has an extended state(e.g., as shown in FIG. 32) configured to cover 318 the distal end ofthe sensor 206 j after the sensor 206 j is removed from the host.

As used herein, the term “retracted” is used broadly and can mean moved,pulled, and/or drawn back. The covers can also be contracted (e.g., madesmaller or shorter).

The cover 318 can be a pliable sheath having a channel 319 in which aportion of the sensor 206 j is located. The cover 318 can be rolled upalong the channel 319.

In some embodiments, the extended state is a relaxed state such that thecover 318 is configured to unroll from the retracted state in responseto the sensor system 202 j being removed from the host.

The retracted state can have higher stored mechanical energy than theextended state such that the cover 318 is configured to unroll from theretracted state in response to the sensor system 202 j being removedfrom the host.

In some embodiments, bellows are configured to expand from a contractedstate to cover a distal end of the sensor. The bellows can help shieldthe distal end of the sensor from piercing skin.

FIGS. 33 and 34 illustrate another type of sensor cover 318 k that canbe part of a system 202 k that comprises a base 204 k, a transmitter 211k, a sensor 206 k, an adhesive 210, and a distal side 207 k. The cover318 k can comprise bellows (e.g., a pleated expandable portion 322)configured to at least partially unfold to enable the cover 318 k tomove from the retracted state to the extended state. The pleatedexpandable portion 322 can be configured to collapse to expose a distalend of the sensor 206 k. The expandable portion 322 can comprise apleated collapsible portion.

FIGS. 33 and 34 illustrate perspective views of the system 202 k. InFIG. 33, the cover 318 k is in an extended state to cover the sensor 206k. In FIG. 34, the cover 318 k is in a retracted state (e.g., when thebase 204 k is coupled to skin of a host). In the retracted state of thecover 318 k, a distal end of the sensor 206 k is located distallyrelative to a distal end of the cover 318 k.

The pleated expandable portion 322 can comprise a channel 319 k in whicha first portion of the sensor 206 k is located. The cover 318 k cancomprise a distal hole 323 through which a second portion of the sensor206 k passes in the retracted state.

The retracted state can have a higher stored mechanical energy than theextended state such that the pleated expandable portion 322 isconfigured to expand from the retracted state in response to the sensorsystem 202 k being removed from the host. The formed channel 319 k mayconstrain the sensor 206 k within a coaxial column.

A cap such as a tube or a silicone stopper can be placed over a distalend of the sensor and can be coupled to the base. The cap can shield thesensor from piercing skin.

The cap can be shaped like a thimble that covers a small areaimmediately around the portion of the sensor configured to be placed intissue. In some embodiments, the cap is much larger and can couple to aperimeter of the base. In some cases, larger caps are easier for peopleto handle.

FIG. 35 illustrates a perspective view of a system 202 m. The system 202m can comprise a cap 325 that covers a distal end of the sensor 206 msuch that the cap 325 is configured to prevent the distal end frompenetrating a person after the sensor system 202 m is removed from thehost and the cap 325 is coupled to the distal side 207 m of the base 204m. A transmitter 211 m can be coupled to the base 204 m.

FIG. 36 illustrates a side, cross-sectional view of the system 202 mshown in FIG. 35. FIG. 37 illustrates a side view of the system 202 m.In FIG. 37, the cap 325 has been removed.

Referring now to FIGS. 35-37, the cap 325 can comprise a channel 319 mand/or a cavity having a first central axis. The base 204 m can comprisea hole 327 having a second central axis. A portion of the sensor 206 mcan pass through the hole 327 and into a channel 319 m. The firstcentral axis can be within twenty degrees of parallel to the secondcentral axis. The first central axis of the channel 319 m can passthrough the hole 327 of the base 204 m (e.g., as the first central axisextends beyond a proximal end of the channel 319 m).

FIGS. 35 and 36 illustrate a relatively small cap 325. FIG. 37illustrates a much larger cap 37. Referring now to FIG. 37, the system202 m can comprise a cap 326 coupled to the base 204 m. The cap 326 cancover at least a majority of the first adhesive 210. The cap 326 cancover a distal end of the sensor 206 m such that the cap 326 isconfigured to prevent the distal end from penetrating a person after thesensor system 202 m is removed from the host and the cap 326 is coupledto the base 204 m.

The cap 326 can comprise sidewalls 328 that protrude proximally past atleast a portion of an outer perimeter of the sensor system 202 m (and/orpast at least a portion of an outer perimeter of the base 204 m). Thecap 326 can be empty or can be filled with an easily pierceable (e.g.,penetrable) material (e.g., foam). The material can help retain the cap326 in place via friction.

Sensor Cover—Unlocking Device

A transmitter can be coupled to the base. A tool can be configured tofacilitate uncoupling the transmitter from the base. The tool can alsocover a distal end of the sensor to prevent the sensor frominadvertently piercing a person. Thus, the tool can serve two purposes:uncoupling the transmitter and covering the “used” sensor.

The tool can be a portion of the insertion device and/or packaging of areplacement sensor. In some embodiments, the tool is packaged with thereplacement sensor.

Users often want to reuse their transmitter. The tool that allows usersto detach their transmitter for reuse with another base also covers thesensor. Thus, the system obligates users to cover their sensor in orderto reuse their transmitter. The dual purposes of the tool promotes moreconsistent use of the tool than would be the case if the tool onlycovered the sensor (but did not unlock the transmitter).

A flex arm can couple the transmitter to the base. The tool can includea protrusion that enters a hole in the base to unlatch the flex arm (touncouple the transmitter from the base). The sensor can be shielded inan interior area of the tool.

FIGS. 38-41 illustrate a tool configured to facilitate uncoupling atransmitter from a base. The tool can also cover a distal end of thesensor to prevent the sensor from inadvertently piercing a person.

FIG. 38 illustrates a perspective view as the sensor system 202 n ismoving towards the tool, but prior to the sensor system 202 n beinginserted at least partially into the tool. FIG. 39 illustrates aperspective, cross-sectional view of the sensory system 202 n movingtowards the tool.

FIG. 40 illustrates a side, cross-sectional view of the sensor system202 n “docked” with the tool to unlatch the transmitter 211 n from thebase 204 n and to cover the sensor 206 n. Once the transmitter 211 n isunlatched from the base 204 n, the transmitter 211 n can move away fromthe base 204 n and out of the tool (e.g., as shown in the perspectiveview of FIG. 41).

Once the transmitter 211 n is unlatched from the base 204 n, the usercan apply a force to manually separate the transmitter 211 n from thebase 204 n. In some embodiments, once the transmitter 211 n is unlatchedfrom the base 204 n, the transmitter 211 n automatically separates fromthe base 204 n, moves away from the base 204 n, and/or moves relative tothe base 204 n in response to inserting the sensor system 202 n into thetool. The tool may contain a spring or deflecting member that assiststhe automatic separation by biasing the transmitter away from the tool.

Some embodiments comprise a sensor cover 330 having an interior area 331and a protrusion 333. At least a portion of the base 204 n can belocated in the interior area 331 of the sensor cover 330 such that adistal end of the sensor 206 n is located between the base 204 n and thesensor cover 330. The protrusion 333 can be located in a channel 334(e.g., a hole) of the base 204 n such that the protrusion 333 unlatchesthe transmitter 211 n from the base 204 n.

The system 202 n can comprise a sensor cover 330 configured to unlockthe transmitter 211 n from the base 204 n in response to coupling thebase 204 n to the sensor cover 330. The transmitter 211 n can beconfigured to be uncoupled from the base 204 n once the transmitter 211n is unlocked from the base 204 n.

The system 202 n can comprise a first flex arm 335 and a wall 336. Thefirst flex arm 335 and the wall 336 can form a latch assembly. The firstflex arm 335 can comprise a first state in which the first flex arm 335interferes with the wall 336 to lock the transmitter 211 n to the base204 n.

The sensor cover 330 can comprise a protrusion 333 configured such thatcoupling the base 204 n to the sensor cover 330 causes the protrusion333 to move the first flex arm 335 to a second state in which the firstflex arm 335 does not interfere with the wall 336 such that the firstflex arm 335 does not lock the transmitter 211 n to the base 204 n.

The base 204 n can comprise a channel 334 (e.g., a hole) in a distalside 207 n of the base 204 n. At least a portion of the protrusion 333can pass through the hole to deflect the first flex arm 335 to thesecond state. The distal side 207 n can comprise adhesive 210 to couplethe base 204 n to the skin of the host.

The sensor cover 330 can comprise a housing 338 and a second flex arm339. The housing 338 can comprise an interior area 331. At least aportion of the base 204 n can be located inside the interior area 331 ofthe housing 338. The second flex arm 339 can couple the protrusion 333to the housing 338 such that the second flex arm 339 is configured tobend to move the protrusion 333 to facilitate inserting the portion ofthe base 204 n into the interior area 331 of the housing 338.

The second flex arm 339 can be configured to move in a distal directionin response to coupling the base 204 n to the sensor cover 330. Thefirst flex arm 335 can be configured to move in a proximal direction inresponse to coupling the base 204 n to the sensor cover 330. A portionof the sensor 206 n can be bent in response to coupling the base 204 nto the sensor cover 330 such that a distal end of the sensor 206 n islocated between the base 204 n and the sensor cover 330.

The sensor cover 330 can comprise a first side 340 and a second side 341(labeled in FIG. 40). The first side can be oriented within plus orminus thirty degrees of perpendicular to the second side. The first sidecan comprise a first channel 343 (e.g., a first hole) through which theportion of the base 204 n is inserted. The second side can comprise asecond channel 344 (e.g., a second hole) configured to provide access toa proximal surface 342 of the transmitter 211 n to facilitate removingthe transmitter 211 n from the base 204 n. (The first channel 343 andthe second channel 344 are labeled in FIG. 41).

The system 202 n can comprise a rail 347. The rail 347 can slidablycouple the base 204 n to the transmitter 211 n.

The system 202 n can comprise a sensor cover 330 configured to unlatchthe transmitter 211 n from the base 204 n in response to coupling thebase 204 n to the sensor cover 330. The system 202 n can comprise afirst flex arm 335 configured to latch the base 204 n to the transmitter211 n. The sensor cover 330 can comprise a second flex arm 339configured to deflect the first flex arm 335 to unlatch the transmitter211 n from the base 204 n.

The sensor cover 330 can comprise a distally facing wall 336. At least aportion coupled to the base 204 n (e.g., a proximal side of the base 204n) can be pressed against the distally facing wall 336 such that aprotrusion 333 of the second flex arm 339 is pressed into a channel 334(e.g., a hole) of the base 204 n to deflect the first flex arm 335.

Telescoping Assembly

FIGS. 42-47 illustrate a system 202 p that comprises a spring 350 thatis configured to retract a distal end of the sensor 206 p into the base204 p (e.g., after the sensor 206 p has been deployed). Once the sensor206 p is retracted, the sensor 206 p cannot pierce the skin of anotherperson.

The spring 350 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

The system 202 p can comprise an assembly 351 configured to movedistally to insert the sensor 206 p and proximally to retract the sensor206 p. The assembly 351 can lock in a distal position configured to holdthe sensor 206 p in the tissue 352 of the host (e.g., as shown in FIG.46). The assembly 351 can unlock to enable the spring 350 to move thesensor 206 p proximally into an interior area 353 of the base 204 p. Insome embodiments, rotating the assembly 351 relative to the base 204 pcauses the assembly 351 to unlock and move proximally. The assembly 351can be a telescoping assembly.

FIG. 42 illustrates a perspective view of the system 202 p. FIG. 43illustrates a top view of the system 202 p. FIG. 44 illustrates aperspective, cross-sectional view along line 44-44 from FIG. 43. In FIG.44, the assembly 351 is located in a proximal position. FIG. 45illustrates the same perspective, cross-sectional view as FIG. 44 exceptthat the assembly 351 is located in a distal position with the sensor206 p in a deployed state. FIG. 46 illustrates a side, cross-sectionalview taken along line 46-46 from FIG. 43. In FIG. 46, the assembly 351is located in the distal position. FIG. 47 illustrates a perspectiveview of the cross section shown in FIG. 46. Many components are hiddenin FIG. 47 to permit clear viewing of particular features.

Referring now to FIGS. 42-47, the transmitter 211 p can be integratedinto the base 204 p. The transmitter 211 p can comprise a battery (e.g.,such that a battery is integrated into the base 204 p). The transmitter211 p can comprise a communication system configured to communicate witha remote computing device.

The transmitter 211 p can be removable from the base 204 p orpermanently coupled to the base 204 p. The base 204 p can comprise adistal side 207 p. Adhesive 210 p can couple the distal side 207 p tothe skin 352 of a host.

The spring 350 can retract the sensor 206 p through a channel 354 (e.g.,a hole) in the base 204 p in a direction 355 within plus or minus thirtydegrees of a proximal direction 208 and/or within plus or minus thirtydegrees of a central axis of the distal end of a sensor 206 p.

The system 202 p can include a locking mechanism configured to securethe spring 350 and the sensor 206 p in a distal position (e.g., in whichthe sensor 206 p is configured to be located in the tissue). Pressingdistally on the locking mechanism (relative to the base 204 p) can movethe sensor 206 p distally, insert the sensor 206 p into the tissue, andsecure the locking mechanism in a distal state.

Pressing the locking mechanism distally a second time, moving aremovable pull tab, manually activating a radially deflecting arm,and/or rotating the locking mechanism (relative to the base 204 p) canrelease the locking mechanism to enable the spring 350 to moveproximally to retract the sensor 206 p proximally out of the tissue andinto a protective cavity 353 of the system 202 p.

The system 202 p can comprise a telescoping assembly 351 coupled to thebase 204 p. At least a first portion of the sensor 206 p can be locatedbetween a portion of the telescoping assembly 351 and a distal side 207p of the base 204 p such that the telescoping assembly 351 is configuredto move from a distal position to a proximal position to retract asecond portion of the sensor 206 p into a protective cavity 353 of thesystem 202 p.

The base 204 p can comprise an interior channel 357 having a proximallyfacing opening. The telescoping assembly 351 can be located at leastpartially in the interior channel 357 such that the telescoping assembly351 is configured to move proximally at least partially in the interiorchannel 357 from the distal position to the proximal position.

When the telescoping assembly 351 is in the distal position, the firstportion of the sensor 206 p can be located in the interior channel 357of the base 204 p, and the second portion of the sensor 206 p can belocated distally relative to the base 204 p. When the telescopingassembly 351 is in the proximal position, the first and second portionsof the sensor 206 p can be located in the interior channel 357 of thebase 204 p.

The telescoping assembly 351 can comprise a first section 358 and asecond section 359. The first section 358 can be slidably coupled to thesecond section 359. The second section 359 can be slidably coupled to aninterior channel 357 of the base 204 p such that the telescopingassembly 351 is configured to telescope relative to the base 204 p toretract the sensor 206 p.

The interior channel 357 can comprise a first overhang 360 (which can beoriented radially inward, radially outward, and/or in any suitabledirection). The first overhang 360 can be configured to interfere with asecond overhang 361 (which can be oriented radially outward, radiallyinward, and/or in any suitable direction) of the second section 359 toretain at least a portion of the second section 359 within the interiorchannel 357. The first overhang 360 and the second overhang 361 can forman interlock configured to couple the assembly 351 to the base 204 p.(The first overhang 360 and the second overhang 361 are labeled in FIG.44.)

The second section 359 can comprise a third overhang 363 (which can beoriented radially inward). The third overhang 363 can be configured tointerfere with a fourth overhang 364 (which can be oriented radiallyoutward) of the first section 358 to limit a distance the first section358 can move proximally relative to the second section 359. (The thirdoverhang 363 and the fourth overhang 364 are labeled in FIG. 44.) Thethird overhang 363 and the fourth overhang 364 can form an interlockconfigured to couple the first section 358 to the second section 359.

The system 202 p can comprise a spring 350 and a locking mechanism. Thelocking mechanism can be configured to lock the telescoping assembly 351in the distal position. The locking mechanism can comprise a firstoverhang 368 of the base 204 p (labeled in FIG. 44) and a secondoverhang 369 of the first section 358. The first and second overhangscan be configured such that in a first angular position of the firstsection 358 relative to the base 204 p, the first overhang 368interferes with the second overhang 369 to limit proximal travel of thefirst section 358 relative to the base 204 p. In some embodiments, in asecond angular position of the first section 358 relative to the base204 p, the first overhang 368 does not limit the proximal travel of thefirst section 358 relative to the base 204 p such that the spring 350pushes the telescoping assembly 351 to the proximal position. Rotatingthe first section 358 relative to the base 204 p can place the firstoverhang 368 in an open area 370 (labeled in FIG. 47) of the firstsection 358, which can permit the first section 358 to move proximallyrelative to the base 204 p.

The base 204 p can comprise a first overhang 360 configured to limit afirst proximal travel of the second section 359 relative to the base 204p. The base 204 p can comprise a second overhang 368 configured toimpede proximal movement of the first section 358 such that thetelescoping assembly 351 is held in the distal position.

The base 204 p can comprise a first channel 372. The second section 359can comprise a radially outward protrusion 373 located in the firstchannel 372 such that the first channel 372 limits a first angularmovement of the second section 359 relative to the base 204 p while thesecond section 359 permits a second angular movement of the firstsection 358 relative to the second section 359 and relative to the base204 p.

The sensor 206 p can comprise a deformable connection 375 thatcommunicatively couples (and/or electrically couples) a subcutaneousportion of the sensor 206 p to a connection portion of the sensor 206 p.(The deformable connection 375 is labeled in FIG. 47.) The connectionportion of the sensor 206 p can be located inside the base 204 p and cancommunicatively couple the subcutaneous portion of the sensor 206 p to acommunication module of the sensor system 202 p.

In the proximal position, the subcutaneous portion of the sensor 206 pcan be located within a center region of a coil (e.g., a deformableconnection) of the sensor 206 p. In many embodiments, the deformableconnection 375 is configured such that the subcutaneous portion of thesensor 206 p is not located in a center region of the deformableconnection.

In some embodiments, the deformable connection 375 of the sensor 206 pdoes not apply a biasing force. In several embodiments, the coil of thesensor 206 p can apply a biasing force to push the telescoping assembly351 to the proximal position. In many embodiments, a spring 350 appliesa biasing force.

The system 202 p can comprise a housing (e.g., the assembly 351)slidably coupled to the base 204 p. The housing can move proximallyrelative to the base 204 p to retract the sensor 206 p.

At least a first portion of the sensor 206 p can be located between aportion of the housing and a distal side 207 p of the base 204 p suchthat the housing is configured to move from a distal position to aproximal position to retract a second portion of the sensor 206 p.

The base 204 p can comprise an interior channel 357 having a proximallyfacing opening. The housing can be located at least partially in theinterior channel 357 such that the housing is configured to moveproximally at least partially in the interior channel 357 from thedistal position to the proximal position to retract the second portionof the sensor 206 p into the interior channel 357.

Top Cap

FIGS. 48-50 illustrate a system 202 q that comprises a top cap 381. Thetop cap 381 can comprise a radially outward overhang that allows a userto “grip” the top cap 381 to pull the top cap 381 proximally (e.g., asindicated by the proximal direction arrow 208). Moving the top cap 381proximally relative to the base 204 q can retract the sensor 206 q intoan area between the top cap 381 and the base 204 q. Once the sensor 206q is retracted, the system 202 q prevents the sensor 206 q from piercinga person.

FIG. 48 illustrates a perspective view of the system 202 q. FIG. 49illustrates a side, cross-sectional view of the system 202 q in acompressed (e.g., collapsed) state. Moving the top cap 381 proximallyrelative to the base 204 q can retract the sensor 206 q into anexpandable housing (e.g., bellows) as shown in FIG. 50, which is a side,cross-sectional view of the system 202 q in an expanded state.

Referring now to FIGS. 48-50, a proximal portion of the sensor 206 q canbe coupled to the cap 381 such that pulling the cap 381 away from thebase 204 q pulls a distal portion of the sensor 206 q into an areabetween the base 204 q and the cap 381 (e.g., as shown in FIG. 50). Oncethe distal portion is located within a cavity 382 of the system 202 q,the sensor 206 q cannot pierce the skin of another person. Bellows cancouple the proximal cap 381 to the base 204 q.

The cap 381 can be a proximal portion of the base 204 q. The base 204 qcan also include a distal portion that couples the proximal portion ofthe base 204 q to the adhesive 210 q and/or to the skin of the host. Theadhesive 210 q can be coupled to the distal side 207 e of the base 204q.

The system 202 q can comprise a cap 381 coupled to the base 204 q andlocated proximally relative to the base 204 q. A first portion of thesensor 206 q can be coupled to the cap 381. The system 202 q can beconfigured such that moving the cap 381 proximally relative to the base204 q retracts the sensor 206 q.

The cap 381 can be movable between a distal position (e.g., as shown inFIG. 49) and a proximal position (e.g., as shown in FIG. 50). In thedistal position, a second portion of the sensor 206 q can be locateddistally relative to the base 204 q. In the proximal position, thesecond portion of the sensor 206 q can be located proximally relative tothe base 204 q. An interlock 384 can removably secure the cap 381 in thedistal position.

At least a portion of an outer perimeter 385 of the cap 381 can protrudefarther radially outward (relative to a central axis of the secondportion) than the base 204 q such that the outer portion of the outerperimeter 385 provides a distally facing wall 386 to enable a user togrip the cap 381 as the user moves the cap 381 from the distal positionto the proximal position.

The system 202 q can comprise a linkage 388 between the cap 381 and thebase 204 q. The linkage 388 can be configured to limit a distance thatthe cap 381 can move proximally relative to the base 204 q.

The linkage 388 can comprise a pleated, collapsible and expandableportion 389 (e.g., bellows) configured to at least partially unfold toenable the cap 381 to move from the distal position to the proximalposition to retract the second portion of the sensor 206 q into thepleated, collapsible and expandable portion 389. The cap 381 can berigidly coupled (and/or removably coupled) to the transmitter 211 q suchthat moving the transmitter 211 q retracts the sensor 206 q proximally.

Biased Sensor

A sensor can be biased such that the relaxed state of the distal portionof the sensor is approximately perpendicular to a distal direction. As aresult, when the sensor is removed from the tissue, the sensorautomatically bends towards its lowest energy state (e.g., such that thesensor points to the side rather than points distally). In thisorientation, the sensor is very unlikely to pierce the skin of anotherperson.

The sensor, needle, and/or an anchoring structure coupled to a sensorand/or a needle can be elastically deformed for insertion by anapplicator. The applicator can hold the distal portion of the sensor inan orientation in which the sensor is pointed distally. As a result, abiased sensor can be held in an insertion orientation by an applicator.Once the applicator and any other impediments (e.g., tissue) areremoved, the biased sensor and/or the needle can automatically movetowards its relaxed state.

FIG. 51 illustrates a side, cross-sectional view of a system 202 r witha biased sensor 206 r. In FIG. 51, the sensor 206 r is in a relaxedstate (or at least a lower energy state than when the sensor 206 r isheld in a distally pointing direction).

FIG. 52 illustrates a side, cross-sectional view of a telescopingapplicator 402 configured to hold the sensor 206 r in a distallyoriented state (e.g., a constrained state). The applicator 402 comprisesa channel 403 configured to prevent the sensor 206 r from returning tothe state of the sensor 206 r shown in FIG. 51.

Moving the proximal portion of the applicator 402 distally (e.g., in thedistal direction 209) moves the sensor 206 r into the tissue 352 of thehost. Once the applicator 402 reaches a distal ending position (e.g., asshown in FIG. 53), the applicator 402 can be removed because the tissue352 resists the sensor 206 r moving to the sensor 206 r orientationshown in FIG. 51. FIG. 53 illustrates a side, cross-sectional view ofthe sensor 206 r in a deployed state prior to the applicator 402 beingremoved from the sensor 206 r.

The applicator 402 can be uncoupled from the base 204 r. Removing thebase 204 r from the tissue 352 allows the sensor 206 r to return to thestate shown in FIG. 51. As illustrated in FIG. 51, a portion of thesensor 206 r is located in a protective slot 302 r of the base 204 r. (Aprotective slot 302 is also shown in FIG. 24.) A transmitter 211 r canbe coupled to the base 204 r. Adhesive 210 can couple the base 204 r tothe tissue 352 of the host.

In some embodiments, the system 202 r comprises a central axis 404oriented from a proximal end of the system 202 r to the distal side 207r of the base 204 r. A distal portion of the sensor 206 r can comprise arelaxed state in which the distal portion is oriented within plus orminus 45 degrees of perpendicular to the central axis 404 of the system202 r such that the relaxed state is configured to reduce a likelihoodof the distal portion penetrating a person (e.g., as illustrated in FIG.51).

The distal portion of the sensor 206 r can comprise a constrained stateoriented within plus or minus 20 degrees of parallel to the central axis404 (labeled in FIG. 51) such that the distal portion is orienteddistally (e.g., as illustrated in FIG. 52). The constrained state hashigher stored mechanical energy than the relaxed state.

The system 202 r can comprise a channel 403 oriented within plus orminus 20 degrees of parallel to the central axis 404 (labeled in FIG.51). A section of the sensor 206 r can be located in the channel 403such that the channel 403 orients the distal portion of the sensor 206 rin the constrained state (e.g., as illustrated in FIG. 52).

As illustrated in FIG. 52, the channel 403 can comprise a slot 302 r.The distal portion of the sensor 206 r can be biased away from the slot302 r such that a bias of the distal portion of the sensor 206 r isconfigured to facilitate maintaining the distal portion of the sensor206 r in the channel 403. The sensor 206 r can be biased directly awayand/or in a direction at least partially away from the slot 302 r. Asused herein, “away” does not necessarily mean “directly away.”

The system 202 r can comprise a telescoping applicator 402 having thechannel 403. The applicator 402 can be removably coupled (and/orpermanently coupled) to the base 204 r such that the applicator 402 isconfigured to orient the distal portion of the sensor 206 r in theconstrained state. The applicator 402 can be configured to be uncoupledfrom the base 204 r such that the distal portion of the sensor 206 r iscapable of entering the relaxed state.

The system 202 r can comprise a telescoping applicator 402 having adistal portion 405 and a proximal portion 406. The proximal portion 406of the applicator 402 can be configured to move distally relative to thedistal portion 405 of the applicator 402 to insert the distal portion ofthe sensor 206 r into the skin.

The distal portion 405 of the applicator 402 can comprise a C-shapedchannel 403 (e.g., as illustrated in FIG. 52). A section of the sensor206 r can be located in the C-shaped channel 403 such that the C-shapedchannel 403 orients the distal portion of the sensor 206 r in theconstrained state. The applicator 402 can be configured such that theproximal portion 406 of the applicator 402 moves distally relative tothe C-shaped channel 403 to insert the distal portion of the sensor 206r into the skin.

The base 204 r can be coupled to the proximal portion 406 of theapplicator 402 such that the base 204 r is configured to move distallyrelative to the C-shaped channel 403 and relative to the distal portion405 of the applicator 402 as the sensor 206 r is inserted into the skin.

Any of the features described in the context of FIGS. 2-53 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 2-53 can becombined with the embodiments described in the context of FIGS. 1 and54-126. Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way (e.g., one, two, three, or more embodiments may be combinable inwhole or in part). Further, any of the features of an embodiment may bemade optional to other aspects or embodiments. Any aspect or embodimentof a method can be performed by a system or apparatus of another aspector embodiment, and any aspect or embodiment of a system can beconfigured to perform a method of another aspect or embodiment.

Buckling Support

Measuring analyte data often involves inserting an analyte sensor intosubcutaneous tissue. Some embodiments use a needle to facilitateinserting the sensor into subcutaneous tissue. Some embodiments have asensor configured to be inserted into subcutaneous tissue without theaid of a needle. (Embodiments can be used with or without a needle.)

Inserting a sensor into a person can cause the sensor to buckle due tothe resistance of the skin and subcutaneous tissue to sensor insertion.For example, the sensor can buckle as a distal tip of the sensorattempts to pierce the skin and/or after the distal tip has pierced theskin as the sensor is moved deeper into the person. Many systems solvethis problem by using a needle to help insert the sensor into theperson. Needles, however, can cause long-term patient discomfort, andthus, are typically removed (while leaving the sensor at least partiallyinside in the person).

In some embodiments, using a needle may have several disadvantages. Forexample, retracting the needle can require extra steps, time, and/orhardware. In addition, the presence of a needle may create a largerwound than necessary for inserting a sensor. For example, a woundcreated by a needle to insert a sensor may be larger than a woundcreated to insert a sensor without a needle. Thus, in some cases,systems and methods that eliminate the need for using a needle to inserta sensor into a person are advantageous.

In some embodiments, one key to enabling systems and methods that do notuse a needle is to eliminate sensor buckling. A system that eliminatessensor buckling typically does not need a needle. Thus, in some casesthere is a need for systems and methods that eliminate sensor bucklingsuch that a needle is not necessary to insert the sensor into theperson.

The entire contents of the following applications are incorporated byreference herein: U.S. patent application Ser. No. 12/893,850; filedSep. 29, 2010; and titled Transcutaneous Analyte Sensor; U.S. patentapplication Ser. No. 14/250,320; filed Apr. 10, 2014; and titled Sensorsfor Continuous Analyte Monitoring, and Related Methods; U.S. patentapplication Ser. No. 13/780,808; filed Feb. 28, 2013; and titled Sensorsfor Continuous Analyte Monitoring, and Related Methods; and U.S. PatentApplication 62/244520; filed Oct. 21, 2015; and titled TranscutaneousAnalyte Sensors, Applicators Therefor, and Associated Methods.

Material Type and Dimensions

Some embodiments enable needle-free sensor insertion by using a sensormade from a material that has sufficient resistance to buckling. Forexample, the sensor materials can have a high modulus of elasticityand/or a high bending stiffness. While these embodiments can reduce thelikelihood of sensor buckling, they also can cause in vivo patientdiscomfort (because a sensor that is stiff may be less prone tobuckling, but can be so stiff that it is uncomfortable for the patientduring chronic use).

Some embodiments enable needle-free sensor insertion by using a sensorwith dimensions that make the sensor not prone to buckling. Severalembodiments have sensors that are not prone to buckling due to the shortlength and/or large width (e.g., diameter) of the sensors.

When a force is applied to insert a sensor (e.g., a self-insertingsensor), buckling can occur before, during, and/or after skinpenetration. The resistance of the sensor to buckling is typicallydependent on several variables such as material properties and geometry(e.g., overall shape, cross-section geometry, thickness of the beam,length of the beam). Subtle elements such as straightness of the beam aswell as induced moments from the load can have large effects on thebuckling performance of the sensor.

A maximum buckling load of a sensor can be predicted using the Eulermodel (shown in FIG. 54). The variables of the Euler model can be usedto represent a wide variety of column shapes and support scenarios:

-   -   F=maximum or critical force (vertical load on column)    -   E=modulus of elasticity    -   I=area moment of inertia of the cross section of the rod    -   L=unsupported length of column    -   K=column effective length factor, whose value depends on the        conditions of end support of the column.

For one end fixed and the other end free to move laterally: K=2.0. KL isthe effective length of the column.

Sensors sometimes have circular cross sections, in which case, the areamoment of inertia of the cross section of the rod can be approximated bythe formulas shown in FIGS. 55 and 56.

As can be seen by the Euler model, the maximum buckling load of a beamwith a circular cross-section increases with radius to the fourth power(for a given material). The maximum buckling load of the beam is dividedby the length squared. As a result, doubling the length results in amaximum buckling load that is just 25% as much as the buckling loadbefore doubling the length (for a given support condition).

The ability of the sensor to resist buckling is typically not the onlyconsideration. The sensor sometimes must retain sufficient flexibilityto avoid causing patient discomfort when the sensor is located at leastpartially inside the patient. The sensor also must reach deeply enoughbelow the skin surface to reliably measure analyte indications (e.g., tomeasure glucose in the interstitial fluid). A sensor that buckles duringinsertion can fail to penetrate the skin. A sensor that buckles afterinsertion can cause unreliable analyte measurements.

In some embodiments, the sensor comprises a diameter of greater than0.004 inches and/or less than 0.015 inches. In several embodiments, thesensor comprises a non-circular cross section, but has a width that isgreater than 0.004 inches and/or less than 0.015 inches. The sensor cancomprise an insertion depth of greater than 2 mm and/or less than 8 mm(under the skin surface).

Collapsible Supports

Long, slender sensors can minimize patient discomfort, but can be highlysusceptible to buckling. Several embodiments comprise support structuresconfigured to resist lateral movements of the sensor as the sensor isinserted into the patient. One challenge, however, is creating a supportstructure that resists buckling forces of the sensor while not blockingdistal movement of the sensor. In other words, a support structure thatholds the sensor such that the sensor does not buckle during insertioncan get in the way of the sensor as the sensor moves distally. Thus, insome cases there is a need for support structures that resist bucklingwhile not impeding distal movement of the sensor.

Several embodiments include a collapsible support member configured toresist non-axial forces of the sensor. Collapsible support members canresist buckling forces and can also compress, deflect, and/or release toallow the sensor to move distally.

In some embodiments, the system comprises a collapsible support memberconfigured to resist non-axial forces of the sensor. The collapsiblesupport member can comprise a proximal end, a distal end, and a lengthmeasured from the proximal end to the distal end. The system can beconfigured to reduce the length in response to moving the sensor from aproximal position to a distal position.

As used herein, axial forces place a central axis of a sensor incompression or tension. Non-axial forces act in directions other thanalong the central axis.

In several embodiments, a collapsible support member comprises achannel. At least a portion of the sensor can pass through the channel.The channel can be configured to resist a buckling force of the sensoras the sensor moves from the proximal position to the distal position.

Collapsible Foam

FIG. 57 illustrates a perspective view of a system 202 s with acollapsible support that resists buckling of the sensor 206 s. Thecollapsible support can be a collapsible block 412 that has a channel413. The sensor 206 s can pass through the channel 413 such that thechannel 413 resists buckling forces while the collapsible block 412compresses to enable the sensor 206 s to move distally.

FIG. 58 illustrates a side view of the system 202 s in a state prior tocompressing the collapsible block 412. FIG. 59 illustrates a side viewof the system 202 s in a state after compressing the collapsible block412 to deploy the sensor 206 s.

The channel 413 starts at a proximal portion 411 of the base and ends ata distal portion 204 s of the base such that the channel 413 passesthrough the block 412. The block 412 can be a cube, a cylinder, a cone,and/or any suitable shape.

FIG. 58 illustrates a distal side 207 s of the system 202 s. Adhesive210 s can couple the distal side 207 s to the skin of a host. FIG. 58also illustrates a distal direction 209 and a proximal direction 208.

A proximal portion 411 of the base can move towards a distal portion 204s of the base (e.g., in the direction shown by arrow 209) while theblock 412 prevents the sensor 206 s from buckling. The block 412 cancompress to enable the system 202 s to deploy the sensor 206 s. Atransmitter 211 s can be coupled to the proximal portion 411 of thebase.

One advantage of a collapsible block 412 is that the structure providesrobust lateral support such that the block 412 prevents the sensor 206 sfrom buckling. For example, FIG. 58 illustrates a lateral direction 414.When the sensor 206 s starts to move in this lateral direction 414,further lateral movement of the sensor 206 s is blocked by a wall of thechannel 413. (The channel 413 can appear like the inside of a tube.)

Another advantage is that the structure of the block 412 is also highlycompressible such that a height of the block 412 can decreasedramatically to enable the system 202 s to move the sensor 206 sdistally.

Referring now to FIGS. 57-59, the block 412 can be made from foam and/orany other suitable material. The foam can be open or closed cell foam.Open cell foam can be highly compressible. High compressibility canreduce the minimum height of the system 202 s in a compressed state.Each foam enables a compression ratio (i.e., the ratio between theuncompressed height of the foam and the compressed height of the foam).In several embodiments, the compressed height of the foam is at least 1percent, at least 10 percent, at least 20 percent, less than 25 percent,less than 35 percent, and/or less than 50 percent of the uncompressedheight of the foam.

The foam can be anisotropic or isotropic. Foams can use a wide varietyof materials including polyurethane, polystyrene, polymer, silicone,and/or any suitable material.

The system 202 s can comprise a foam coupled to the base 204 s and achannel 413 mechanically supported by the foam. At least a portion ofthe sensor 206 s can be located in the channel 413. The portion of thesensor 206 s can comprise a central axis. The channel 413 can beconfigured to resist lateral displacement of the portion of the sensor206 s relative to the central axis. The foam can be configured tocompress in response to the system 202 s moving the sensor 206 s from aproximal position (e.g., as illustrated in FIG. 58) to a distal position(e.g., as illustrated in FIG. 59).

In some embodiments, the base comprises a distal portion 204 s and aproximal portion 411. The system 202 s can comprise a channel 413 havingwalls configured to compress in response to the system 202 s moving thesensor 206 s from a proximal position to a distal position. The channel413 can be located at least partially between the distal portion 204 sand the proximal portion 411 of the base such that a portion of thesensor 206 s is located in the channel 413. The walls of the channel 413can be configured to resist lateral displacement of the portion of thesensor 206 s. This lateral displacement is defined relative to a distaldirection 209 along a central axis of a portion of the sensor 206 slocated in the channel 413.

In several embodiments, the walls comprise foam configured to compressin response to moving the proximal portion 411 distally towards thedistal portion 204 s of the base.

The walls can be made from collapsible structures and/or compressiblematerials other than foam.

The foam block 412 can have one or more intermediate layers made out ofa more rigid and/or less compressible material. The layers of the foamblock 412 can be adhered together. The intermediate layer 416 can be amore rigid foam. The intermediate layer 416 can be plastic, silicone,thermoplastic elastomer (“TPE”), and/or an elastomer such that the foamcompresses at least 50 percent while the intermediate layer 416compresses less than 25 percent.

The intermediate layer 416 can be located between a proximal layer 417and a distal layer 418. The intermediate layer 416 can have a differentmaterial than the distal layer 418 and the proximal layer 417. Theintermediate layer 416 can have a higher density, can be lesscompressible, can be harder (e.g., as measured on the Shore A scale),can have a higher modulus of elasticity, can be stiffer, and/or can bemore rigid than the distal layer 418 and/or the proximal layer 417. Theintermediate layer 416 can have a closed-cell structure while the distallayer 418 and/or the proximal layer 417 have an open-cell structure.

In some embodiments, the walls comprise a proximal section (e.g., aportion of the proximal layer 417) having a first material, anintermediate section (e.g., a portion of the intermediate layer 416)having a second material, and a distal section (e.g., a portion of thedistal layer 418) having a third material. The second material can bemore rigid than the first and third materials such that the intermediatesection is configured to resist the lateral displacement. The secondmaterial can be stiffer than the first and third materials such that theintermediate section is configured to resist the lateral displacement.The second material can be less compressible than the first and thirdmaterials.

In several embodiments, the system 202 s comprises an interlock 420(e.g., a mechanical interlock) configured to secure the proximal portion411 of the base to the distal portion 204 s of the base in response tothe system 202 s moving the sensor 206 s from the proximal position tothe distal position.

A mechanical interlock 420 can secure the system 202 s in the compressedstate (as shown in FIG. 59). The mechanical interlock 420 can includearms and a snap fit that couples with an undercut or channel 413. Thechannel 413 can be formed by a hole, a pass through, or a slot.

Collapsible Bellows

FIGS. 60-63 illustrate a system 202 t with a collapsible support thatresists buckling of the sensor 206 t. The collapsible support can beformed by bellows 421 that have a channel 422. A portion of the sensor206 t can be located in the channel 422 of the bellows 421. The sensor206 t can pass through the channel 422 such that the channel 422 resistsbuckling forces while the bellows 421 compress to enable the sensor 206t to move distally. Adhesive 210 t can couple the system 202 t to aperson.

FIG. 60 illustrates a perspective view of the system 202 t in a stateprior to collapsing the bellows 421 (shown in FIG. 61). FIG. 61illustrates a side view of the system 202 t in the state prior tocollapsing the bellows 421. FIG. 62 illustrates a side, cross-sectionalview of the state shown in FIGS. 60 and 61. The sensor 206 t can move ina distal direction 209 relative to the base 204 t to compress thebellows 421 while the bellows 421 resist buckling of the sensor 206 t.FIG. 63 illustrates a side, cross-sectional view of a state aftercollapsing the bellows 421 to deploy the sensor 206 t.

Referring now to FIGS. 60-63, the bellows 421 can comprise pleatedexpansible parts made from an elastomeric material, a rigid plastic, aflexible plastic, a silicone, and/or a flexible polymer. The bellows 421can include foldable sections configured to fold to enable the bellows421 to compress from an initial height to a compressed height that isless than 50 percent and/or less than 35 percent of the initial height(measured in the proximal direction 208).

The system 202 t can include arms 427 configured to guide a top portion(e.g., the transmitter 211 t) towards the base 204 t to control thecollapse of the bellows 421. The arms 427 can support and position thetop portion as the bellows 421 collapse such that the movement of thearms 427 translates into movement of the top portion relative to thebase 204 t and the at least partial collapse of the bellows 421. Thearms 427 can be configured to guide the top portion in a linear mannertowards the base 204 t or can be configured to rotate the top portionrelative to the base 204 t as the bellows 421 are compressed.

The bellows 421 can be configured to laterally support at least aportion of the sensor 206 t as the portion passes through an interiorarea (e.g., a channel 422) of the bellows 421. The system 202 t can beconfigured such that moving the system 202 t from an initial state (inwhich the sensor 206 t is not at least partially located in the person)to a final state (in which the sensor 206 t is located at leastpartially in the person) can cause the bellows 421 to collapse.

Several embodiments do not include a needle. Some embodiments include aneedle (e.g., as shown in embodiments incorporated by reference) that isretracted into the bellows 421. The system 202 t can include a springthat has a relaxed state such that the bellows 421 are expanded (e.g.,the needle is retracted and/or the sensor 206 t is not deployed). Thearms 427 can act as a spring system.

The system 202 t can include a mechanical interlock 429 configured toreleasably hold the bellows 421 and/or a spring in a compressed state.Releasing the mechanical interlock 429 can retract the sensor 206 t fromthe skin such that the portion of the sensor 206 t that was locateddistally relative to the distal side 207 t of the base 204 t is movedproximally into an interior area of the system 202 t. The interlock 429can be a snap fit formed by an undercut (e.g., as shown in FIG. 63).

In some embodiments, the system 202 t comprises bellows 421 coupled tothe base 204 t. At least a portion of the sensor 206 t can be located inan interior area of the bellows 421. The portion of the sensor 206 t cancomprise a central axis. The bellows 421 can be configured to resistlateral displacement of the portion relative to the central axis. Thebellows 421 can be configured to compress in response to the system 202t moving the sensor 206 t from a proximal position to a distal position.

The system 202 t can include a removable safety feature 424 configuredto prevent premature and/or inadvertent sensor deployment. A tab 425 canbe coupled to the safety feature such that moving the tab 425 (e.g., ina direction shown by arrow 426) moves the safety feature 424 relative tothe base 204 t to uncouple the safety feature 424 from the base 204 t.The safety feature 424 can be C-shaped. For example, the safety feature424 can be shaped like a hoop with an open section configured to enablethe bellows 421 to pass through the open section as the safety feature424 is removed.

Some embodiments comprise a distal portion of the base 204 t and aproximal portion (which can include the transmitter 211 t). The bellows421 can couple the distal portion to the proximal portion. The system202 t can comprise a removable interference member 424 (e.g., a safetymember) located between the distal portion and the proximal portion suchthat the removable interference member 424 is configured to block thesystem 202 t from moving the sensor 206 t from the proximal position(e.g., a proximal starting position) to the distal position (e.g., adistal ending position).

In some embodiments, the system comprises a tab coupled to thecollapsible support member. The system can be configured such thatactuating (e.g., pulling, pushing, moving, pressing, touching) the tabcauses the collapsible support member to collapse and causes at least aportion of the sensor to move distally relative to the base.

Folded Flex Tab

FIGS. 64-67 illustrate a system 202 u with a collapsible support thatresists buckling of the sensor 206 u. The collapsible support can beformed by a compliant sheet 438 located in a slot 439 (e.g., apassageway, a hole, a channel) of a housing 440. Moving the sheet 438distally can cause the sensor 206 u to move distally (e.g., into tissueof the host). The housing 440 can comprise a slot 439 configured toresist buckling forces of the sensor 206 u as the sensor 206 u movesdistally (e.g., as indicated by the distal arrow 209 shown in FIG. 66).

FIG. 64 illustrates a perspective view of the system 202 u, which caninclude a battery 430 u and a transmitter 211 u that can be electricallycoupled to a flex circuit 431 located at least partially in the slot439. FIG. 65 illustrates a different perspective view of the system 202u. Moving the sheet 438 in a direction that is within plus or minus 45degrees of perpendicular to the distal direction 209 (shown in FIG. 66)can move a portion of the sheet 438 located in the slot 439 distally tomove the sensor 206 u distally. For example, the sheet 438 can be movedin direction 432 and/or in direction 433, which can cause the sheet 438to move the sensor 206 u in direction 434 (e.g., a distal direction).

The system 202 u can include a distal side 207 u having adhesive 210 uconfigured to couple the system 202 u to the skin of a host. The sheet438 can couple the adhesive 210 u to the base 204 u and/or to thehousing 440.

FIG. 66 illustrates a side view of the housing 440 that includes a slot439. The slot 439 can go all the way through the housing 440 (e.g., froma left side to a right side of the housing 440) as illustrated in FIG.66. In some embodiments, the slot 439 does not go all the way throughthe housing 440.

FIG. 67 illustrates a perspective view of the system 202 u without thehousing 440. The proximally protruding portion 436 of the sheet 438 isconfigured to fit within the slot 439 of the housing 440 (shown in FIG.66). Moving this portion 436 distally causes the system 202 u to movethe sensor 206 u distally.

Referring now to FIGS. 64-67, several embodiments include at least onetab 446, 447 coupled to a flexible member (e.g., the sheet 438). Theflexible member and a portion of the sensor 206 u can be located in aslot 439 such that moving the tab 446, 447 causes the flexible member tomove, push, and/or pull the portion of the sensor 206 u out of the slot439 and into tissue of a person.

The slot 439 can support the sensor 206 u by resisting buckling forcesof the sensor 206 u. The slot 439 can have an opening 448 that facesdistally (labeled in FIG. 66). The slot 439 can support at least 80% ofthe ex vivo portion of the sensor 206 u (e.g., when the sensor 206 u isin a proximal starting position prior to sensor deployment). The slot439 can be located in a housing 440, which can be a removableapplicator.

The system 202 u can comprise a pull tab 446, 447 and a slot 439configured such that at least a portion of the sensor 206 u is locatedin the slot 439. The system 202 u can be configured such that pullingthe pull tab 446, 447 causes the system 202 u to move the sensor 206 ufrom a proximal position to a distal position.

The system 202 u can comprise a compliant sheet 438 located in the slot439 and coupled to the pull tab 446, 447 such that the compliant sheet438 is configured to move (e.g., push, pull) the portion of the sensor206 u distally in response to actuating (e.g., pulling) the pull tab446, 447. As used herein, the sheet 438 is “compliant” if the sheet 438can conform and/or bend to fit in the slot 439.

The system 202 u can comprise a housing 440 coupled to the base 204 u.The housing 440 can comprise the slot 439 and can be configured to causethe compliant sheet 438 to push the portion of the sensor 206 u distallyin response to pulling the pull tab 446, 447. The slot 439 can comprisea distally facing opening 448 (labeled in FIG. 66) configured to allowthe portion of the sensor 206 u to exit the slot 439 distally and entersubcutaneous tissue of the host.

High-Level Claims-Guide Members and Splitting Channels

As described above, long, slender sensors can be highly susceptible tobuckling. Several embodiments comprise support structures configured toresist lateral movements of the sensor as the sensor is inserted intothe patient. One challenge, however, is creating a support structurethat resists buckling forces of the sensor while not blocking distalmovement of the sensor. Some embodiments avoid blocking distal movementof the sensor by moving out of the way of the sensor as the sensor movesdistally.

In some embodiments (e.g., as described in the context of FIGS. 74-84),systems can comprise a guide member configured to resist non-axialforces of the sensor. Thus, a guide member can brace the sensor againstbuckling.

The guide member can comprise an engagement feature releasably coupledto the sensor. The engagement feature can be configured to uncouple fromthe sensor in response to moving the sensor from a proximal position toa distal position.

In several embodiments, a guide member comprises a first portion and asecond portion. At least a portion of the sensor can be located betweenthe first and second portions of the guide member such that the firstand second portions of the guide member are configured to resist abuckling force of the sensor.

In some embodiments, the first portion can be configured to moverelative to the second portion of the guide member in response to thesystem moving the sensor from a proximal position to a distal position.The guide member can be configured such that displacement of the firstportion relative to the second portion permits moving the sensor fromthe proximal position to the distal position.

In several embodiments, the portion of the sensor (that is locatedbetween the first and second portions of the guide member) comprises acentral axis. The first and second portions of the guide member can forma channel. The portion of the sensor can be located in the channel. Thechannel can be configured to resist displacement of the portion of thesensor in a direction perpendicular to the central axis.

Splitting Channel

In some embodiments (e.g., as described in the context of FIGS. 74-84),systems can comprise a channel having a first side and a second sideconfigured to at least partially separate in response to the systemmoving the sensor from a proximal position to a distal position. Aportion of the sensor can be located in the channel such that thechannel is configured to at least partially separate to permit thesensor to move from the proximal position to the distal position. Theportion of the sensor can comprise a central axis. The channel can beconfigured to resist displacement of the portion of the sensor in adirection perpendicular to the central axis.

Splinter Insertion

FIGS. 68-70 illustrate a system 202 v that includes a guide member(e.g., a channel located at least partially between a first portion anda second portion of a base 204 v). The guide member can support thesensor 206 v to prevent harmful buckling. The guide member can include acurved and/or angled portion configured to deflect a distal portion ofthe sensor 206 v into the skin of the host. As a result, moving thesecond portion of the base 204 v relative to the first portion of thebase 204 v can cause a distal portion of the sensor 206 v to changedirections.

FIG. 68 illustrates a perspective view of the system 202 v. Moving thesecond portion of the base 204 v (e.g., as indicated by arrow 451)relative to the first portion of the base 204 v can cause the sensor 206v to be deflected by the system 202 v and exit a distal side 207 v ofthe base 204 v. Adhesive 210 can couple the distal side 207 v to skin ofthe host.

FIG. 69 illustrates the same pre-deployment state as shown in FIG. 68.FIG. 69 illustrates a side, cross-sectional view. Sliding the secondportion of the base 204 v in the direction indicated by arrow 452 pushesthe sensor 206 v along an interior area between the first portion andthe second portion of the base 204 v. Continuing to slide the secondportion of the base 204 v in the direction indicated by arrow 452 causesa distal portion of the sensor 206 v to protrude from the distal side207 v of the base 204 v (e.g., as shown in FIG. 70). FIG. 70 illustratesa side, cross-sectional view of the system 202 v in a state in which thesensor 206 v is deployed.

Referring now to FIGS. 68-70, a first portion of the system 202 v can bemoved approximately horizontally to push the sensor 206 v out of adistal side 207 v of the base 204 v. In some embodiments, the firstportion of the system 202 v can be configured to move in a directionthat is within plus or minus 45 degrees and/or within plus or minus 25degrees of perpendicular to a distal direction 209. The first portioncan be coupled to the base 204 v by a rail 457 such that the firstportion is slidably coupled to the base 204 v.

A curved channel 455 (which can be a slot) can deflect the sensor 206 vsuch that movement of the top portion causes the sensor 206 v to exitthe distal side 207 v of the base 204 v. The movement can be in adirection that is within plus or minus 45 degrees and/or within plus orminus 25 degrees of perpendicular to a distal direction 209.

The sensor 206 v is prevented from inadvertently buckling by beingconstrained between the first portion and the second portion of the base204 v. The system 202 v can comprise a channel 456 configured to resistbuckling forces of the sensor 206 v as the sensor 206 v is deployed. Thechannel 456 can be approximately straight and can be coupled with acurved and/or angled channel 455.

In several embodiments, a sensor 206 v is coupled to a housing 454 thatis slidably coupled to the base 204 v. The system 202 v can beconfigured to move a portion of the sensor 206 v away from the distalside 207 v of the base 204 v (and into the skin) in response to movingthe housing 454 in a first direction (e.g., as indicated by arrow 452)within plus or minus 10 degrees, within plus or minus 20 degrees, withinplus or minus 45 degrees, and/or within plus or minus 60 degrees ofperpendicular to a distal direction 209.

The system 202 v can comprise a housing 454 slidably coupled to the base204 v. The base 204 v can comprise a channel 455 (e.g., a curved channeland/or a channel oriented at an angle within plus or minus 45 degrees ofparallel to a distal direction 209). A portion of the sensor 206 v canbe located in the channel 455. The sensor 206 v can move through thecurved and/or angled channel 455 as the sensor 206 v is deployed intothe skin. The channel 455 can be configured to deflect the portion ofthe sensor 206 v to redirect the portion distally in response to movingthe housing 454 relative to the base 204 v.

A sensor path can have a first section 456 and a second section 455. Atleast a portion of the sensor 206 v can move along the first section 456and the second section 455 of the sensor path. The first section 456 canbe oriented within plus or minus 20 degrees of perpendicular to a distaldirection 209 and/or within plus or minus 45 degrees of perpendicular toa distal direction 209. The second section 455 can be oriented withinplus or minus 45 degrees of parallel to the distal direction 209. Thesystem 202 v can be configured to deflect the sensor 206 v to cause thesensor 206 v to follow the sensor path such that the channel 455redirects the sensor 206 v towards the skin of the host.

The base 204 v can comprise a first portion (e.g., the portion thatcomprises the distal side 207 v) and a second portion (e.g., the portionthat comprises the transmitter 211 v). The first portion can beconfigured to couple the second portion to the skin. The second portioncan be slidably coupled to the first portion. The base 204 v can beconfigured such that moving the second portion (relative to the firstportion) in a first direction (e.g., as shown by arrow 452) within plusor minus 20 degrees of perpendicular to a distal direction 209 (and/orwithin plus or minus 45 degrees of perpendicular to a distal direction209) causes a distal tip of the sensor 206 v to move in a seconddirection within plus or minus 45 degrees of parallel to the distaldirection 209.

The sensor 206 v can comprise a distal section and a proximal section.The proximal section can be rigidly coupled to the second portion of thebase 204 v. The distal section can pass through a channel 455, 456 ofthe first portion of the base 204 v. The channel 455, 456 can comprise aradius configured to deflect at least a portion of the sensor 206 v suchthat the portion of the sensor 206 v is redirected distally towards theskin of the host.

The sensor 206 v can be a glucose sensor and/or any type of sensordescribed herein and/or incorporated by reference. The transmitter 211 vcan be coupled to the second portion of the base 204 v such that thesecond portion slidably couples the transmitter 211 v to the firstportion of the base 204 v. The system 202 v can comprise at least onerail 457 that slidably couples the second portion to the first portionof the base 204 v. In some embodiments, the first and second portionsmay be coupled to a spring. In several embodiments, the sliding membermay be shrouded internally to protect the mechanism from externalinfluences.

Curved Support Channel

FIGS. 71-73 illustrate a system 202 w that includes a guide member(e.g., a channel 463). Some embodiments maintain the sensor 206 w in anapproximately straight orientation to minimize buckling. However, otherembodiments (e.g., as shown in FIGS. 71-73) deliberately bend the sensor206 w along a curved path to enable buckling forces that actuallyfacilitate successful sensor 206 w insertion. Thus, the system 202 w candirect the buckling forces in a known, repeatable, predictabledirection. A wall of a channel 463 can support the sensor 206 w in thisdirection to preclude harmful buckling.

FIG. 71 illustrates a perspective view of the system 202 w. FIG. 72illustrates a perspective, cross-sectional view of the system 202 w in astate prior to the sensor 206 w being deployed (e.g., when the sensor206 w is in a proximal starting position). FIG. 73 illustrates a side,cross-sectional view of the system 202 w in a state after the sensor 206w is deployed (e.g., when the sensor 206 w is in a distal endingposition).

The base 204 w can rotate distally (e.g., as indicated by arrow 461 inFIG. 72) relative to the applicator 462 to move the sensor 206 w intothe tissue (e.g., as illustrated in FIG. 73). Adhesive 210 w can couplethe distal side 207 w of the base 204 w to the skin of the host.

The system 202 w can include a curved channel 463 configured to supportthe sensor 206 w as the sensor 206 w is deployed into the skin of theperson. The curved channel 463 can be part of an applicator 462 that isremovably coupled to the base 204 w.

The system 202 w can include a spring 464 (e.g., a leaf spring 464) in aflexed state when the sensor 206 w is in a proximal starting position(e.g., as shown in FIG. 72). A mechanical interlock 467 (e.g., an inwardprotrusion) can hold the spring 464 in the flexed state. Releasing themechanical interlock 467 enables the spring 464 to push the sensor 206 wto a distal position as a portion of the sensor 206 w follows a curvedpath through the curved channel 463. Deflecting the protrusion (e.g., bypulling a pull tab 465 or by any other suitable means) can release themechanical interlock 467.

The spring 464 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

The curved nature of the channel 463 determines the predominantdirection of buckling forces. As a result, the buckling forces press thesensor 206 w towards the bottom of the channel 463 (rather than out ofthe channel 463). The support provided by the curved channel 463 onpredominantly one hemisphere of a cross section of the sensor 206 wallows more force to transfer to the distal tip of the sensor 206 w. Theresult is highly reliable sensor 206 w insertion.

The system 202 w can comprise a removable applicator 462 coupled to thebase 204 w. The base 204 w can include a transmitter (e.g., as shown inother embodiments). The applicator 462 can be any type of applicator 462described herein and/or incorporated by reference.

The applicator 462 can comprise a curved channel 463 configured to guidea portion of the sensor 206 w along a curved path as the portion of thesensor 206 w moves from a proximal position (e.g., as shown in FIG. 72)to a distal position (e.g., as shown in FIG. 73). (In some embodiments,the channel 463 is straight rather than curved.) The applicator 462 cancomprise a leaf spring 464 configured to drive the portion of the sensor206 w along the curved path through the curved channel 463.

A curved channel 463 can be coupled to the base 204 w. A curved portionof the sensor 206 w can be located in the curved channel 463. The curvedchannel 463 can be configured to resist buckling forces of the curvedportion as the system 202 w moves the curved portion from a proximalposition (e.g., as shown in FIG. 72) to a distal position (e.g., asshown in FIG. 73). The applicator 462 can be configured to facilitatemoving the curved portion of the sensor 206 w from the proximal positionto the distal position.

The system 202 w can comprise a spring 464 configured to move the curvedportion of the sensor 206 w from the proximal position to the distalposition. The spring 464 can be any type of spring 464 described hereinand/or incorporated by reference. The spring 464 can be a leaf spring ina flexed state.

The system 202 w can comprise an interlock 467 (e.g., a mechanicalinterlock) configured to releasably hold the spring 464 (e.g., a leafspring) in a flexed state. FIG. 72 illustrates an interlock 467 thatcomprises an inward protrusion of the applicator 462 that interfereswith distal movement of a portion of the system 202 w (e.g., a portionof the spring 464, a portion of the base 204 w).

The system 202 w can be configured to move the curved portion of thesensor 206 w from the proximal position to the distal position inresponse to releasing the interlock 467. The system 202 w can comprise atab 465 (e.g., a pull tab) coupled to the interlock 467 such the system202 w is configured to disengage the interlock 467 to enable the spring464 to move the curved portion of the sensor 206 w from the proximalposition to the distal position in response to actuating (e.g., pulling,pushing, moving) the tab 465.

Sensor Grip—Zipper Embodiment

Some embodiments use movable arms to support the sensor against bucklingforces. The movable arms can move out of the way as the sensor movesfrom a proximal starting position to a distal ending position.

The movable arms can have many different shapes. In some embodiments,the movable arms can be shaped like a clothespin, opposing fingers,and/or a set of tongs. The movable arms can have a relaxed state inwhich the moveable arms form a channel through which at least a portionof the sensor passes as the sensor is deployed.

In several embodiments, the movable arms have a relaxed state in whichthe arms are spread apart from each other. The applicator can hold thearms together to support the sensor against buckling.

FIGS. 74-77 illustrate a system 202 x that includes a guide member(e.g., a channel 473). The system 202 x can comprise a channel 473having a first side and a second side configured to at least partiallyseparate in response to the system 202 x moving the sensor 206 x from aproximal position to a distal position.

FIG. 74 illustrates a side view of a base 204 x. A transmitter 211 x islocated inside the base 204 x. A sensor 206 x is coupled to the base 204x. Adhesive 210 x is coupled to a distal side 207 x of the base 204 xsuch that the adhesive 210 x is configured to couple the base 204 x toskin of the host.

FIG. 75 illustrates a perspective, cross-sectional view of a telescopingapplicator 475 that is removably coupled to the base 204 x. Theapplicator 475 includes four sets of arms 474. Each set of arms 474includes a first arm 474 and a second arm 474. The first arm 474 and thesecond arm 474 of each set can press towards each other (such that therelaxed state of the first arm 474 and the second arm 474 is when theend portions of the first arm 474 and the second arm 474 touch eachother). In the area where the first arm 474 and the second arm 474 toucheach other, the arms 474 can form a channel 473. At least a portion ofthe sensor 206 x can be configured to pass through the channel 473. Thechannel 473 can resist buckling forces of the sensor 206 x to helpmaintain the portion of the sensor 206 x in an approximately straightconfiguration as the sensor 206 x is deployed.

A proximal portion 476 of the applicator 475 can include a distalprotrusion 478 configured to enter an area 479 between each set of arms474 as the proximal portion 476 of the applicator 475 moves towards thedistal portion 477 of the applicator 475. As the distal protrusion 478enters the area 479 between each set of arms 474, the distal protrusion478 can move the first arm 474 away from the second arm 474 to open thechannel 473 to allow an angled portion 469 of the sensor 206 x to passbetween each set of arms 474.

FIG. 76 illustrates a side, cross-sectional view of the system 202 xwhen the system 202 x is in a proximal starting position. The distalprotrusion 478 can move in the direction indicated by arrow 470 as thesystem 202 x moves the base 204 x in a distal direction 209 (e.g., asindicated by arrow 471).

FIG. 77 illustrates a side, cross-sectional view of the system 202 x asthe system 202 x is moving the sensor 206 x distally. An end portion ofeach arm 474 can include an indentation that faces an indentation of anopposing arm 474. When the end portions of arms 474 touch each other(and/or are close to each other), the indentations can form channels 473configured to support the sensor 206 x against buckling forces. Thesensor 206 x can be at least partially located in each channel 473formed by each set of arms 474. Thus, the system can include multiple,concentric channels 473.

A first channel can have a central axis that passes through a secondchannel located distally relative to the first channel (e.g., as shownin FIG. 77). The first channel can be formed by a first set of arms. Thesecond channel can be formed by a second set of arms.

Referring now to FIGS. 74-77, a system 202 x can include multiple setsof paired, movable, flexible arms 474. As the system 202 x moves thesensor 206 x from the proximal starting position to the distal endingposition, the system 202 x can push each set of arms 474 apart to enablethe bent section (e.g., the angled portion 469) of the sensor 206 x topass through each set of arms 474. Each set of moveable arms 474 canopen before the bent section of the sensor 206 x reaches each set ofmoveable arms 474.

A distal protrusion 478 (e.g., a part of the applicator 475 and/or apart of a sensor module support) can enter an area 479 between each setof movable arms 474 to flex the arms 474 to an expanded state. Atelescoping assembly 475 can move the protrusion distally relative tothe movable arms 474 to expand each set of arms 474.

The system 202 x can comprise a first arm 474 and a wall coupled to thebase 204 x. (The wall can be a surface of a second arm 474.) A portionof the sensor 206 x can be secured between the first arm 474 and thewall such that the first arm 474 is configured to resist buckling forcesof the sensor 206 x as the system 202 x moves the portion of the sensor206 x from a proximal position to a distal position.

The first arm 474 can be movably coupled to the base 204 x such that atleast a portion of the first arm 474 is configured to move (e.g.,relative to the base 204 x, relative to a housing of an applicator 475)to enable the system 202 x to move the portion of the sensor 206 x fromthe proximal position to the distal position.

At least one of the first arm 474 and the wall can form a channel 473.The portion of the sensor 206 x can be at least partially located in thechannel 473 such that the channel 473 is configured to resist thebuckling forces. The system 202 x can comprise a distal protrusion 478configured to move the first arm 474 away from the wall to enable thesystem 202 x to move the portion of the sensor 206 x from the proximalposition to the distal position. The portion of the sensor 206 x cancomprise a central axis. The first arm 474 can protrude in a directionwithin plus or minus 45 degrees of perpendicular to the central axis.

The system 202 x can comprise a removable applicator 475 having atelescoping assembly that is removably coupled to the base 204 x. Thetelescoping assembly can comprise a first set of tongs configured toresist a first buckling force of a first section of the sensor 206 x.

Each set of arms 474 can form a set of tongs. As used herein, “tongs” isused broadly. Tongs can mean a tool used for holding objects, whereinthe tool is made of two pieces connected at one end, in approximatelythe middle, and/or at any suitable location. The tongs can hold thesensor. In some embodiments, the tongs form a channel, but might nottouch the sensor unless the sensor starts to buckle slightly such thatthe buckling causes the sensor to touch the tongs.

The telescoping assembly can comprise a second set of tongs (e.g., asecond set of arms 474) configured to resist a second buckling force ofa second section of the sensor 206 x. The telescoping assembly cancomprise a distal protrusion 478 configured to move distally into afirst area between the first set of tongs and into a second area betweenthe second set of tongs to expand the first and second sets of tongs.

Sensor Grip—Clamp Embodiment

In some embodiments, the arms are oriented at an angle within plus orminus 60 degrees of perpendicular to a distal direction 209 (e.g., asshown in FIGS. 75-77). In several embodiments, arms 474 y are orientedat an angle of plus or minus 45 degrees of parallel to a distaldirection 209 (e.g., as shown in FIGS. 78-81).

FIGS. 78-81 illustrate a clamp 480 configured to support the sensor 206y as the sensor 206 y moves distally. This support can prevent thesensor 206 y from buckling as the sensor 206 y is inserted at leastpartially into a host.

The clamp 480 can be configured to open after a distal end of the sensor206 y pierces the skin. Thus, the clamp 480 can support the sensor 206 yagainst buckling forces until the system 202 y has overcome the peakbuckling forces of sensor insertion. The clamp 480 constrains and/orsupports at least a portion of the sensor 206 y. As a result, the clamp480 reduces the effective column length of the sensor 206 y. Asdescribed herein, reducing the column length can dramatically increasethe buckling resistance of the sensor 206 y.

In some embodiments, the clamp 480 does not compress the sensor 206 y,but instead allows the sensor 206 y to move distally between a first arm474 y of the clamp 480 and a second arm 474 y of the clamp 480. Thefirst and second arms 474 y can form a first channel 484 through whichthe sensor 206 y can pass as the sensor 206 y moves distally. Otherembodiments prevent sensor movement (relative to the arms 474 y) byclamping the sensor 206 y until the clamp 480 releases the sensor 206 y.In other words, the clamp 480 can apply a compressive force on thesensor 206 y to help secure the sensor 206 y.

The system 202 y can comprise a second channel 483 configured to holdthe first and second arms 474 y of the clamp 480 in a compressed stateuntil the first and second arms 474 y reach a distal point at which thesecond channel 483 widens or ends. At this point, the first and secondarms 474 y can move away from each other towards a relaxed state of thefirst and second arms 474 y. (The second channel 483 can be a lumen.)

In some embodiments, the clamp 480 is biased such that the lowest energystate of the clamp 480 is when the first arm 474 y touches the secondarm 474 y. The system 202 y can include features (e.g., a protrusion ofthe applicator 475 y) configured to defect the arms 474 y away from eachother to open the clamp 480 (and move the clamp 480 into a higher energystate). Thus, the arms 474 y can be flexed outward due to an input forceapplied by a user.

Moving the first and second arms 474 y away from each other can enable astructure that supports a bent section of the sensor 206 y to movebetween the first and second arms 474 y to continue pushing the sensor206 y deeper into the person. (FIG. 74 illustrates a bent section 469.)

FIG. 78 illustrates a perspective view of the system 202 y in a proximalstarting position. FIG. 79 illustrates a side, cross-sectional view ofthe system 202 y in the proximal starting position. The clamp 480supports the sensor 206 y against buckling forces to help maintain atleast a portion of the sensor 206 y in an approximately straightconfiguration.

FIG. 80 illustrates a side, cross-sectional view of the system 202 y ina position between the proximal starting position and a distal endingposition. As illustrated in FIG. 80, the clamp 480 has opened to enablethe system 202 y to continue moving the base 204 y distally relative toa distal portion 477 y of the applicator 475 y. The sensor 206 y hasalready pierced the skin. As a result, the sensor 206 y has typicallyalready passed the peak buckling forces of the sensor insertion cycle.Thus, in some embodiments, supporting the sensor 206 y with the clamp480 is no longer necessary after the sensor 206 v has pierced the skin352.

The applicator 475 y can comprise a proximal portion 476 y and a distalportion 477 y. The proximal portion 476 y can be configured to move(e.g., telescope) relative to the distal portion 477 y to move thesensor 206 y and/or the base 204 y distally towards the skin of thehost.

FIG. 81 illustrates a side, cross-sectional view of the system 202 y asthe system 202 y approaches a distal ending position. In someembodiments, the adhesive 210 y (labeled in FIG. 78) is configured toadhere to the skin 352 (shown in FIG. 81) in the distal ending position.

Referring now to FIGS. 78-81, the system 202 y can comprise a removableapplicator 475 y coupled to the base 204 y. The base 204 y can include atransmitter. The applicator 475 y can have a pair of biasing members(e.g., a set of tongs). The pair of biasing members can be a pair ofarms 474 y configured to move relative to each other and configured toresist buckling of at least a portion of the sensor 202 y.

The pair of biasing members can comprise a first arm 474 y coupled to asecond arm 474 y such that the arms 474 y are configured to flexrelative to each other. A portion of the sensor 206 y can be located inan area between the pair of biasing members such that the pair ofbiasing members is configured to resist buckling forces of the sensor206 y (e.g., as shown in FIG. 79).

The pair of biasing members can be held in a compressed state by achannel 483 configured to enable the pair of biasing members to expandin response to moving the pair of biasing members far enough distallythat a distal end of the sensor 206 y is located distally relative to adistal side 485 (labeled in FIG. 80) of the applicator 475 y. The pairof biasing members can be a set of tongs.

The system 202 y can comprise a first arm 474 y and a second arm 474 ythat extend distally. A portion of the sensor 206 y can be locatedbetween the first and second arms 474 y such that the first and secondarms 474 y are configured to resist buckling forces of the sensor 206 y.The first and second arms 474 y can be located in a channel 483 of thesystem 202 y. The channel 483 can hold the first and second arms 474 yin a compressed state. The channel 483 can be configured such thatmoving the first and second arms 474 y distally causes the first andsecond arms 474 y to spread apart from each other to facilitate thesystem 202 y moving the portion of the sensor 206 y from a proximalposition to a distal position.

The system 202 y can comprise a first arm 474 y and a second arm 474 ythat extend distally. The first and second arms 474 y can be configuredto have a closed state in which the first and second arms 474 y resistbuckling forces of a portion of the sensor 206 y located between thefirst and second arms 474 y. The first and second arms 474 y can beconfigured to have an open state to enable the system 202 y to move theportion of the sensor 206 y from a proximal starting position to adistal ending position.

Splitting Tube

FIGS. 82-84 illustrate a system 202 z that includes a guide member(e.g., a tube 491). The tube 491 can support the sensor 206 z as thesensor 206 z is inserted into tissue to prevent the sensor 206 z frombuckling.

The system 202 z comprises a channel (e.g., of the tube 491) having afirst side and a second side (formed by the slot 492) configured to atleast partially separate in response to the system 202 z moving thesensor 206 z from a proximal position (e.g., as shown in FIG. 83) to adistal position (e.g., as shown in FIGS. 82 and 84).

FIG. 82 illustrates a perspective view of a system 202 z in a distalposition (e.g., where a distal end of the sensor 206 z) is locatedfarther distally than the applicator 475 z. FIG. 83 illustrates a side,cross-sectional view of the system 202 z in a proximal starting position(e.g., prior to sensor deployment). FIG. 84 illustrates a partial viewfrom the perspective shown in FIG. 82.

Referring now to FIGS. 82-84, the system 202 z comprises a tube 491through which at least a portion of the sensor 206 z can move as thesensor 206 z is driven from a proximal starting position (e.g., as shownin FIG. 83) to a distal ending position (e.g., as shown in FIGS. 82 and84). The tube 491 can resist buckling forces of the sensor 206 z to helpmaintain the portion of the sensor 206 z in an approximately straightconfiguration. Adhesive 210 z can couple a distal side 207 z of the base204 z to skin of a host.

The tube 491 can be a feature of the distal portion 477 z of thetelescoping assembly. For example, a single piece can be molded. Thispiece can include the tube 491 and the other features of the distalportion 477 z.

The tube 491 can be a separate component that is coupled to the distalportion 477 z or to any other portion of the telescoping assembly. Insome embodiments, the distal portion 477 z comprises arms that couplethe tube 491 to the distal portion 477 z.

The tube 491 can support at least a majority of a length of the sensor206 z between (A) the sensor 206 z module and/or the base 204 z and (B)the distal side 490 of the applicator 475 z. The base 204 z can includea transmitter (e.g., as shown in other embodiments).

The applicator 475 z can comprise a telescoping assembly (e.g., theapplicator 475 z). The tube 491 can be coupled to a distal portion 477 zof the telescoping assembly. The sensor 206 z can be coupled to aproximal portion 476 z of the telescoping assembly such that moving theproximal portion 476 z distally relative to the distal portion 477 zmoves a portion of the sensor 206 z through a channel of the tube 491.

The tube 491 can include a slot 492 oriented approximately parallel to acentral axis of the tube 491. The slot 294 can extend from a distal endof the tube 491 to a proximal end of the tube 491. In some embodiments,the slot 492 does not necessarily extend from a distal end to a proximalend of the tube 491, but at least extends from a distal portion to aproximal portion of the tube 491.

The slot 492 can enable a bent portion 469 of the sensor 206 z to movedistally (through the slot 492) as a portion of the sensor 206 z movesdistally within a channel of the tube 491. In some embodiments, the slot492 is at least partially held closed until moving the bent portion 469through the slot 492 causes the slot 492 to open (e.g., by partiallyunrolling the tube 491, by breaking linkages between each side of theslot 492).

The tube 491 can be manufactured using any suitable process. The tube491 can be formed by an extrusion process (with a hoop-shaped crosssection to form the channel). A side of the tube 491 can be cut (e.g.,by a laser and/or by a mechanical cutting blade) to form the slot 492.The cut can extend from a distal end of the tube 491 to a proximal endof the tube 491. In some embodiments, only a portion of a length of thetube 491 is cut.

A side of the tube 491 can be perforated to enable the system 202 z tomove the bent portion 469 of the sensor 206 z distally (by breakingthrough the area of the tube 491 that was weakened by the perforations).The tube 491 can be formed by creating a flat sheet and then rolling thesheet into a tubular shape. In this configuration, the ends of thetubular shape may be overlapping or may create a gap. The tube 491 canbe made from a polymer (e.g., polyimide), metallic foil, silicone,and/or any suitable material.

The system 202 z can include a cutting edge (e.g., a blade made of metalor plastic) configured to cut the tube 491 as the system 202 z moves thesensor 206 z distally to enable the bent portion 469 of the sensor 206 zto move distally through a cutting path of the cutting edge.

The system 202 z can comprise a tube 491 coupled to the base 204 z. Thetube 491 can comprise a slot 492 from a proximal portion of the tube 491to a distal portion of the tube 491. The tube 491 can be configured toresist buckling forces of the sensor 206 z. The slot 492 can beconfigured to enable moving a first portion (e.g., 469) of the sensor206 z distally outside of the tube 491 while moving a second portion ofthe sensor 206 z distally inside the tube 491.

The system 202 z can comprise a removable applicator 475 z coupled tothe base 204 z. The applicator 475 z can couple the tube 491 to the base204 z such that the system 202 z is configured to move the base 204 zdistally relative to the tube 491 to pierce the skin with a distal endof the sensor 206 z. The tube 491 can comprise a first side of the slot492 and a second side of the slot 492. The first and second sides of theslot 492 can be coupled together by a linkage 493 configured to breakopen in response to moving the first portion of the sensor 206 zdistally. The tube 491 can be at least 4 millimeters long as measuredalong a central axis of the tube 491.

The system 202 z can comprise an applicator 475 z having a channel 494configured to resist buckling forces of the sensor 206 z. A distalportion of the sensor 206 z can be located inside the channel 494. Aproximal portion of the sensor 206 z can be located outside the channel494. An intermediate portion of the sensor 206 z can couple the distaland proximal portions of the sensor 206 z. The intermediate portion ofthe sensor 206 z can be located in a slot 492 of the channel 494.

The slot 492 can be configured to enable the intermediate portion of thesensor 206 z to move distally through the slot 492 as the sensor 206 zmoves from a proximal position to a distal position. The channel 494 cancomprise a central axis oriented distally such that the channel 494 isconfigured to guide the distal portion of the sensor 206 z towards theskin. The slot 492 can be oriented radially outward from the centralaxis.

The slot 492 can comprise at least one linkage 493 that couples a firstside of the slot 492 to a second side of the slot 492. The at least onelinkage can be configured to break in response to moving theintermediate portion of the sensor 206 z distally through the slot 492.In some embodiments, the slot 492 is configured to expand (e.g., widen)in response to moving the intermediate portion of the sensor 206 zdistally through the slot 492.

Any of the features described in the context of FIGS. 54-84 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 54-84 can becombined with the embodiments described in the context of FIGS. 1-53 and85-126. Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way (e.g., one, two, three, or more embodiments may be combinable inwhole or in part). Further, any of the features of an embodiment may bemade optional to other aspects or embodiments. Any aspect or embodimentof a method can be performed by a system or apparatus of another aspector embodiment, and any aspect or embodiment of a system can beconfigured to perform a method of another aspect or embodiment.

Additional Applicators

Measuring analyte data often involves inserting an analyte sensor intosubcutaneous tissue. The user can actuate an applicator to insert theanalyte sensor into its functional location (e.g., inside tissue of thehost). This transcutaneous insertion can lead to incomplete sensorinsertion, improper sensor insertion, and unnecessary pain.

Inserting a sensor into a person can cause the sensor to buckle due tothe resistance of the skin and subcutaneous tissue to sensor insertion.For example, the sensor can buckle as a distal tip of the sensorattempts to pierce the skin and/or after the distal tip has pierced theskin as the sensor is moved deeper into the person. Many systems solvethis problem by using a needle to help insert the sensor into theperson. Needles, however, can cause long-term patient discomfort, andthus, are typically removed (while leaving the sensor at least partiallyinside in the person).

Using a needle has several disadvantages. For example, retracting theneedle can require extra steps, time, and/or hardware. Placing a sensorinside or alongside a needle creates a larger wound and therefore alarger wound response in vivo. Thus, in some cases there is a need forsystems and methods that eliminate the need for using a needle to inserta sensor into a person. Many embodiments described herein and/orincorporated by reference enable a user to insert a sensor into tissuewithout using a needle.

Many embodiments do not include a needle. However, all of theembodiments described herein can optionally use a needle to facilitateinserting a sensor into tissue. In some embodiments, sensors comprise aneedle and additional features as described herein.

Several embodiments rely on a distal movement of an applicator in adirection approximately parallel to a central axis of a sensor to insertthe sensor into the tissue of the person. All of the applicatorsdescribed herein and/or incorporated by reference can be used with allof the systems and features described herein and/or incorporated byreference.

Preloaded Spring

FIGS. 85-88 illustrate an applicator 475 aa that includes a distalportion 477 aa and a proximal portion 476 aa. The proximal portion 476aa can hold the base 204 aa in a proximal starting position. Moving theproximal portion 476 aa distally can unlatch the base 204 aa such that acompressed spring 513 can push the base 204 aa and the sensor 206 aadistally. A transmitter can be coupled to the base 204 aa.

The spring 513 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

FIG. 85 illustrates a perspective view of the applicator 475 aa in aproximal starting position. The applicator 475 aa is configured suchthat moving the proximal portion 476 aa distally (e.g., as indicated byarrow 512) relative to the distal portion 477 aa unlatches the base 204aa from the proximal portion 476 aa to enable a compressed spring 513 tomove the base 204 aa and the sensor 206 aa distally (e.g., into skin 352of the host).

FIG. 86 illustrates a side, cross-sectional view of the system 202 aa ina proximal starting position. In some embodiments, the spring 513 is ina compressed state when the system 202 aa is in a proximal startingposition. In several embodiments, moving the proximal portion 476 aa ofthe applicator 475 aa distally relative to the distal portion 477 aacompresses the spring 513 to provide the force that moves the base 204aa and the sensor 206 aa distally. Arrow 208 illustrates a proximaldirection. Arrow 209 illustrates a distal direction.

FIG. 87 illustrates a side, cross-sectional view of the system 202 aa asthe proximal portion 476 aa releases the base 204 aa in response to theproximal portion 476 aa moving distally relative to the distal portion477 aa. The proximal portion 476 aa can move distally (e.g., asindicated by arrow 514) relative to the distal portion 477 aa, which cancause flex arms 516 to be pressed radially outward due to interferingwith actuation features 517 of the distal portion 477 aa. The flex arms516 and/or the actuation features 517 can include ramps 518, 519configured to force the flex arms 516 radially outward (or radiallyinward) in response to the proximal portion 476 aa moving distallyrelative to the distal portion 477 aa. Arrows 522, 523 indicate the arms516 moving radially outward.

The arms 516 and/or others surfaces (e.g., proximally facing surfaces525 labeled in FIG. 86) of the proximal portion 476 aa can resist adistal force of the spring 513. In other words, the arms 516 can holdthe base 204 aa in the proximal starting position and/or can block thebase 204 aa from moving to a distal ending position (e.g., as shown inFIG. 88) until the arms 516 and/or other surfaces of the proximalportion 476 aa release (e.g., uncouple from) the base 204 aa. In FIG.86, the arms 516 block the base 204 aa from moving distally. FIG. 87illustrates the arms 516 flexing radially outward to uncouple from thebase 204 aa to enable the base 204 aa to move distally relative to theproximal portion 476 aa and the distal portion 477 aa of the applicator475 aa (e.g., as indicated by arrow 526).

FIG. 88 illustrates a side, cross-sectional view of the base 204 aaafter the base 204 aa has moved distally. In FIG. 88, the base 204 aa isin a distal ending position (e.g., such that the sensor 206 aa islocated at least partially in the tissue 352 of the host). As shown bythe progression from FIG. 86 to FIG. 87 to FIG. 88, the base 204 aamoves a first distance in response to the proximal portion 476 aa movinga much smaller distance. The magnification of the movement of theproximal portion 476 aa can enable a favorable insertion experiencebecause the user perceives the sensor's insertion depth as being smallerthan is actually the case (due to a perception of the distance of themovement of the proximal portion 476 aa being equal to the depth of thesensor insertion).

Adhesive 210 aa can couple a distal side 207 aa of the base 204 aa tothe skin 352 of the host. The adhesive 210 aa can have any suitableshape.

Referring now to FIGS. 85-88, a telescoping assembly (e.g., theapplicator 475 aa) can be coupled to the base 204 aa. The telescopingassembly can comprise a distal portion 477 aa, a proximal portion 476 aaslidably coupled to the distal portion 477 aa, and a spring 513compressed between the proximal portion 476 aa and the base 204 aa. Theproximal portion 476 aa can releasably secure the sensor 206 aa in afirst proximal starting position such that the spring 513 is configuredto push the base 204 aa and the sensor 206 aa distally in response tothe system 202 aa unlatching the base 204 aa from the proximal portion476 aa.

The proximal portion 476 aa can comprise a latch configured toreleasably secure the base 204 aa in a second proximal startingposition. The latch can comprise an arm 516, a first ramp 518, a secondramp 519, actuation features 517, a proximal facing surface 525, and/orany suitable feature configured to releasably secure the base 204 aa ina position that is proximal to a distal ending position of the base 204aa. The latch can be configured to release the base 204 aa in responseto moving the proximal portion 476 aa distally relative to the distalportion 477 aa to enable the spring 513 to push the base 204 aa and thesensor 206 aa distally.

As described above, a relatively small movement of the applicator 475 aacan result in a larger movement of the base 204 aa and/or the sensor 206aa movement. The sensor 206 aa can be configured to move along a firstpath from the first proximal starting position to a first distal endingposition (e.g., as shown by the progression from FIG. 86 to FIG. 88).The proximal portion 476 aa can be configured to move along a secondpath from a third proximal starting position to a third distal endingposition (e.g., as shown by the progression from FIG. 86 to FIG. 88).The first path of the sensor 206 aa can be at least 20 percent longerand/or at least 40 percent longer than the second path of the proximalportion 476 aa. The system 202 aa can be configured to cause the sensor206 aa to move a first distance in response to the proximal portion 476aa moving a second distance that is at least 50 percent shorter than thefirst distance.

The system 202 aa can comprise arms 516 configured to release the base204 aa and/or the sensor 206 aa to enable the base 204 aa and/or thesensor 206 aa to move distally relative to the proximal portion 476 aaand/or the distal portion 477 aa of the telescoping applicator 475 aa.The proximal portion 476 aa can comprise a distally protruding arm 516having an inward protrusion (e.g., a portion of the ramp 518) thatpasses through a hole 528 (labeled in FIG. 86) of the distal portion 477aa. The hole 528 can be a through hole or can be a partial hole (e.g.,an indentation). The inward protrusion can be coupled to the base 204 aato secure the sensor 206 aa in the first proximal starting position.

The system 202 aa can be configured such that moving the proximalportion 476 aa distally relative to the distal portion 477 aa causes thedistally protruding arm 516 to flex outward to release the inwardprotrusion from the base 204 aa to enable the spring 513 to push atleast a portion of the sensor 206 aa into the skin 352.

The system 202 aa can be configured to move the sensor 206 aa a firstdistance in response to moving the proximal portion 476 aa a seconddistance to unlatch the base 204 aa. The first distance can be at leasttwice as long as the second distance such that the system 202 aa isconfigured to magnify a first movement of the proximal portion 476 aainto a larger second movement of the sensor 206 aa and/or the base 204aa. The distal portion 477 aa can comprise a channel 529 (labeled inFIG. 87) configured to orient the base 204 aa as the spring 513 pushesthe base 204 aa distally.

Twist Tack

Some applicators move a sensor distally in response to distal movementof a portion of an applicator. Other applicators, however, can move asensor into tissue in response to non-distal movements. For example,applicators can move a sensor distally in response to a rotation of aportion of the applicator. The rotation can be about a central axis ofthe applicator. Some applicators move the sensor distally in response toa rotation of a dial. The dial can be a part of the applicator'sexternal body or can rotate independently of the external body.

FIGS. 89-93 illustrate an embodiment in which rotating an outer housing532 relative to a base 204 ab can release a compressed spring 538 todrive the sensor 206 ab into the skin of a host. The outer housing 532can be a dial that is removably coupled to the base 204 ab. The spring538 can be a conical spring 538 to enable a shorter compressed height.

The spring 538 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

A first housing 532 can be rotatably coupled to the base 204 ab. Asecond housing 533 can be coupled to the sensor 206 ab. A spring 538 canbe compressed between a proximal end of the first housing 532 and thesensor 206 ab. The spring 538 can be configured to push the secondhousing 533 and the sensor 206 ab distally relative to the base 204 aband the first housing 532 in response to rotating the first housing 532relative to the base 204 ab.

FIG. 89 illustrates a perspective view of the system 202 ab. The system202 ab can move the sensor 206 ab distally into the skin in response toa user rotating the first housing 532 of the applicator 475 ab relativeto the adhesive 210 ab (e.g., when the adhesive 210 ab is coupled to theskin).

The system 202 ab inherently guards against inadvertent sensor 206 abdeployment because rotating the first housing 532 relative to theadhesive 210 ab and/or the base 204 ab is unlikely unless the base 204ab is coupled to the skin by the adhesive 210 ab. For example, if thesystem 202 ab is not coupled to the skin by the adhesive 210 ab,rotating the first housing 532 will also rotate the adhesive 210 ab, thesensor 206 ab, and the base 204 ab. In some embodiments, this rotationwill not deploy the sensor 206 ab because sensor 206 ab deploymenttypically requires rotating the first housing 532 relative to theadhesive 210 ab and/or the base 204 ab.

FIG. 90 illustrates a perspective view of at least a portion of a base204 ab. A transmitter 211 ab can be coupled to the base 204 ab. Thetransmitter 211 ab can comprise a battery and a wireless communicationsystem configured to communicate with a remote device. Adhesive 210 abcan couple the base 204 ab to skin of the host.

FIG. 91 illustrates a top, cross-sectional view of the system 202 ab.The first housing 532 can be configured to rotate (e.g., as indicated byarrow 541) relative to the second housing 533 and the base 204 ab.

FIG. 92 illustrates a side, perspective, cross-sectional view of thesystem 202 ab with the sensor 206 ab in a proximal starting position. Asillustrated in FIG. 92, the spring 538 can be in a compressed state(e.g., a high-energy state) when the sensor 206 ab is in a proximalstarting position. In some embodiments, the spring 538 is in an extendedstate (e.g., a high-energy state) when the sensor 206 ab is in aproximal starting position.

Rotating the first housing 532 relative to the base 204 ab and/or theadhesive 210 ab enables the spring 538 to move the second housing 533and/or the sensor 206 ab distally to a distal ending position (e.g., asshown in FIG. 93). FIG. 93 illustrates a side, perspective,cross-sectional view of the system 202 ab.

Referring now to FIGS. 89-93, a first housing 532 can be rotatablycoupled to the base 204 ab. A spring 538 can be compressed between aportion of the first housing 532 and the sensor 206 ab. The system 202ab can be configured to unlatch the sensor 206 ab from the first housing532 to enable the spring 538 to move the sensor 206 ab distally inresponse to rotating the first housing 532 relative to the base 204 aband/or the adhesive 210 ab.

The first housing 532 can comprise a first central axis (e.g., arotational axis of the first housing 532). The sensor 206 ab cancomprise a portion configured to pierce the skin. The portion cancomprise a second central axis. The first central axis can be orientedwithin plus or minus twenty degrees of parallel to the second centralaxis.

The spring 538 can be a helical spring and/or a conical springconfigured to expand distally to move the sensor 206 ab distally. Insome embodiments, the spring 538 is any of the types of springsdescribed herein and/or incorporated by reference.

The base 204 ab can comprise a first portion 534 and a second portion535. The applicator 475 ab can be configured to be removed from thesecond portion 535 of the base 204 ab (e.g., while the second portion535 is coupled to the skin by adhesive 210 ab). The applicator 475 abcan retain the first portion 534 of the base 204 ab (e.g., such that thefirst portion 534 of the base 204 ab remains in the applicator 475 abwhile the second portion 535 of the base 204 ab remains coupled to theskin after the applicator 475 ab is uncoupled from the second portion535 of the base 204 ab).

A transmitter 211 ab can be removably coupled to at least a portion ofthe base 204 ab. In some embodiments, the transmitter 211 ab isintegrated into the base 204 ab. In some embodiments, the transmitter211 ab is a portion of the base 204 ab.

A first housing 532 can be rotatably coupled to the base 204 ab. Asecond housing 533 can be coupled to the sensor 206 ab. A spring 538 canbe compressed between a proximal end of the first housing 532 and thesensor 206 ab such that the spring 538 is configured to push the secondhousing 533 and the sensor 206 ab distally relative to the base 204 aband the first housing 532 in response to rotating the first housing 532relative to the base 204 ab.

The second housing 533 can be located in an interior area of the firsthousing 532. The first adhesive 210 ab can be configured to secure thebase 204 ab to the skin to enable the first housing 532 to rotaterelative to the base 204 ab and relative to the second housing 533.

The first housing 532 can comprise a first central axis (e.g., arotational axis). The sensor 206 ab can comprise a portion configured topierce the skin. The portion can comprise a second central axis. Thefirst central axis can be oriented within plus or minus ten degreesand/or within plus or minus 45 degrees of parallel to the second centralaxis. The spring 538 can be a conical spring 538 configured to expand inresponse to rotating the first housing 532 relative to the base 204 ab.

The system 202 ab can comprise a mechanical interlock between the firsthousing 532 and the second housing 533. The mechanical interlock can beconfigured to releasably hold the spring 538 in a compressed state suchthat the sensor 206 ab is in a proximal starting position (e.g., asillustrated in FIG. 92).

The mechanical interlock can comprise a first protrusion 542 of thefirst housing 532 that interferes with distal movement of a secondprotrusion 543 of the second housing 533. The mechanical interlock canbe configured such that rotating the first protrusion 542 relative tothe second protrusion 543 causes the second protrusion 543 to falldistally off the first protrusion 542 and thereby enables the secondhousing 533 to move distally relative to the first housing 532.

The first protrusion 542 can be oriented radially outward, and thesecond protrusion 543 can be oriented radially inward. (In severalembodiments, the first protrusion 542 is oriented radially inward, andthe second protrusion 543 is oriented radially outward.) The mechanicalinterlock can comprise a ridge 545 and a groove 546 configured such thatrotating the first housing 532 relative to the base 204 ab requiresovercoming a torque threshold to move the ridge 545 out of the groove546. The ridge 545 and the groove 546 are shown in FIG. 93. In FIG. 92,the ridge 545 engages the groove 546, but the ridge 545 and the groove546 are not visible.

In some embodiments, the system 202 ab comprises a safety featureconfigured to insert the sensor 206 ab and/or retract the sensor 206 abin response to a distal force on the first housing 532 and a rotation ofthe first housing 532 relative to the adhesive 210 ab. Thus, the system202 ab can be configured to insert the sensor 206 ab and/or retract thesensor 206 ab in response to a combination of a distal “push” and arotational movement (e.g., applied during the “push”).

As illustrated in FIG. 91, the system 202 ab can comprise ananti-rotation interface 547 between the second housing 533 and the base204 ab. The interface 547 can comprise a ridge 548 located in a groove549 configured to limit rotation of the second housing 533 relative tothe base 204 ab during rotation of the first housing 532 relative to thebase 204 ab. The interface 547 can be oriented from a proximal portionof the second housing 533 to a distal portion of the second housing 533.

Scotch Yoke

Some systems convert rotational motion into linear motion in order toinsert a sensor. Systems can hold a sensor in a distal position (e.g.,such that the sensor is fully inserted into the tissue) while otherportions of the system move proximally (e.g., to uncouple the applicatorfrom the sensor). Thus, the system can ensure full sensor insertion isnot jeopardized by the removal of the applicator.

FIG. 74 illustrates a base 204 x and a sensor 206 x. In FIGS. 94-99, thebase 204 x and the sensor 206 x are removably coupled to an applicator475 ac.

The applicator 475 ac is configured to insert the sensor 206 x into theskin of a host. The applicator 475 ac can be configured to convertrotational motion (e.g., caused by a spring force) into a linear motionthat inserts a sensor 206 x into the skin. The applicator 475 ac canblock the sensor 206 x from moving distally until a user presses abutton 567 (e.g., an actuation member). The button 567 can release thespring force to cause a rotational motion that the applicator 475 acconverts into an approximately linear motion that inserts the sensor 206x.

The applicator 475 ac can include a button 567 configured to release atorsional spring 568. The torsional spring 568 causes a rotationalmotion that the system 202 ac converts into linear motion to move thesensor 206 x distally into the skin.

The spring 568 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

The system 202 ac can include two bodies 557, 558, which can movedistally together. The two bodies 557, 558 can be arms.

Once the sensor 206 x has reached its distal ending position, the firstbody 557 moves proximally (to uncouple the first body 557 from the base204 x and/or the sensor 206 x) while the second body 558 holds thesensor assembly distally (to prevent the base 204 x and/or the sensor206 x from moving proximally with the first body 557).

In some embodiments, a first adhesive 210 x couples the sensor assemblyto the skin. A second adhesive 554 couples the first body 557 to thesensor assembly (e.g., the wearable analyte monitor). The second body558 prevents the first adhesive 210 x from having to resist the secondadhesive 554 as the first body 557 moves proximally. In other words,without the second body 558 blocking proximal movement of the sensorassembly, moving the first body 557 proximally could apply a substantialproximal force on the first adhesive 210 x (which could cause the firstadhesive 210 x to uncouple from the skin).

In some embodiments, retention features (e.g., movable arms, clampingarms, snap fits) couple the first body 557 to the sensor assembly. Thesecond body 558 prevents the first adhesive 210 x from having to resistthe retention features as the first body 557 moves proximally. Uniquechannel shapes enable the first body 557 to move proximally while thesecond body 558 holds the sensor assembly down (in the distal position).

FIG. 94 illustrates a side view of the applicator 475 ac with the sensor206 x in a distal ending position (e.g., in tissue of the host). Theapplicator 475 ac can move the sensor 206 x distally in response to auser actuating (e.g., pressing) the button 567.

FIGS. 95-98 illustrate perspective, cross-sectional views of the system202 ac at various moments in an insertion cycle of the sensor 206 x.Portions of the first housing 551 are hidden in FIGS. 95-98 to permitclear viewing of internal features.

A spring 568 (shown in FIG. 99) located inside of a rotating housing 552applies a torsional force between the rotating housing 552 and the firsthousing 551. A protrusion 566 blocks rotational movement of the rotatinghousing 552 relative to the first housing 551. FIG. 95 illustrates theprotrusion 566 located in a channel of the rotating housing 552 to blockrotational movement of the rotating housing 552.

In the state illustrated in FIG. 96, the user has already pressed thebutton 567 (shown in FIG. 94) to move the rotational housing 552 awayfrom the protrusion 566. As a result, the protrusion 566 is no longer inthe channel of the rotational housing, and thus, the protrusion 566 nolonger impedes rotational movement of the rotational housing 552relative to the first housing 551. As a result, the rotational housing552 rotates relative to the first housing 551, which causes the firstbody 557 and the second body 558 to move distally (e.g., as indicated byarrow 570. The distal movement of the first body 557 and/or the secondbody 558 moves the sensor 206 x distally (e.g., as shown in FIG. 97).

FIG. 97 illustrates the sensor 206 x in a distal ending position.Continued rotation of the rotational housing 552 relative to the firsthousing 551 moves the first body 557 proximally (e.g., as indicated byarrow 571), but typically does not (at least immediately or initially)move the second body 558 proximally due to a divergent portion 563(e.g., a proximally curved portion) of the second channel 562 (shown inFIG. 100). As a result, the second body 558 blocks proximal movement ofthe base 204 x and/or the sensor 206 x while the first body 557 detachesproximally from the base 204 x and/or the sensor 206 x. FIG. 98illustrates the system 202 ac after the first body 557 has movedproximally relative to the base 204 x and the second body 558 touncouple the first body 557 from the base 204 x and/or the sensor 206 x.

FIG. 99 illustrates a side view of portions of the system 202 ac. Thefirst housing 551 is hidden in FIG. 99. FIG. 99 illustrates the samestate illustrated in FIG. 98.

FIG. 100 illustrates a side view of the second body 558. The divergentportion 563 of the second channel 562 is clearly visible in FIG. 100. Insome embodiments, the second channel 562 includes a portion that curvesmore proximally than the related portion of the first channel 561 suchthat the first body 557 is configured to impede proximal movement of thebase 204 x and/or the sensor 206 x as the first body 557 movesproximally relative to the base 204 x, the sensor 206 x, and/or thesecond body 558. The protrusion 564 of the rotational housing 552identifies the related portion.

Referring now to FIGS. 94-100, a removable applicator 475 ac can becoupled to the base 204 x. The applicator 475 ac can comprise a rotatinghousing 552 configured to push the first and second bodies 557, 558distally. A second adhesive 554 can couple the base 204 x to the firstbody 557. The second body 558 can be configured to hold the base 204 xin a distal position while the first body 557 moves proximally touncouple the first body 557 from the base 204 x.

The applicator 475 ac can comprise a locking mechanism configured toprevent the first body 557 and/or the second body 558 from movingdistally until the locking mechanism is disengaged. The lockingmechanism can comprise the button 567 and/or the protrusion 566configured to impede rotational movement of the rotational housing 552.

The applicator 475 ac can comprise a locking mechanism configured toblock rotational movement of the rotating housing 552. The system 202 accan be configured to disengage the locking mechanism in response tolinear movement of the rotational housing 552 (e.g., in response toactuation of the button 567).

The system 202 ac can comprise a removable applicator 475 ac coupled tothe base 204 x. The applicator 475 ac can comprise a first housing 551,a second housing 552 rotatably coupled to the first housing 551, and atorsion spring 568. (Some embodiments use other types of springs.) Thetorsion spring 568 can have a first portion coupled to the first housing551 and a second portion coupled to the second housing 552 (e.g., asindicated in FIG. 99) such that the torsion spring 568 is configured torotate the second housing 552 relative to the first housing 551.

The applicator 475 ac can have a first body 557 slidably coupled to thefirst housing 551 and coupled to the second housing 552 such that thefirst body 557 is configured to linearly push the sensor 206 x from aproximal starting position (e.g., as illustrated in FIG. 95) to a distalending position (e.g., as illustrated in FIG. 97) in response to thesecond housing 552 rotating relative to the first housing 551.

The applicator 475 ac can have a second body 558 slidably coupled to thefirst housing 551 and coupled to the second housing 552 such that thesecond body 558 is configured to block proximal movement of the sensor206 x after the sensor 206 x has reached the distal ending position asthe system 202 ac uncouples the first body 557 from the base 204 x.

A second adhesive 554 can couple the first body 557 to the base 204 x.The first and second arms 557,558 can be configured to move linearly anddistally in response to rotating the second housing 552 relative to thefirst housing 551.

The second body 558 can be configured to block the proximal movement ofthe sensor 206 x as rotation of the second housing 552 relative to thefirst housing 551 uncouples the second adhesive 554 from the base 204 xto enable the first body 557 to move proximally relative to the base 204x and relative to the second body 558.

The first body 557 can be coupled to a first linear channel 561. A firstprotrusion 564 can couple the first linear channel 561 to the secondhousing 552. The first linear channel 561 can be configured such that afirst rotational movement of the second housing 552 relative to thefirst housing 551 causes a first distal linear movement of the firstbody 557 relative to the first housing 551.

The second body 558 can be coupled to a second channel 562 having adivergent portion 563. The first protrusion 564 can couple the secondchannel 562 to the second housing 552. The second channel 562 can beconfigured such that the first rotational movement of the second housing552 relative to the first housing 551 causes a second distal linearmovement of the second body 558 relative to the first housing 551.

The divergent portion 563 of the second channel 562 can be configuredsuch that continued rotational movement of the second housing 552relative to the first housing 551 after the sensor 206 x has reached thedistal ending position does not cause proximal movement of the secondbody 558 as the continued rotational movement uncouples the secondadhesive 554 from the base 204 x by moving the first body 557proximally.

The second housing 552 can be coupled to the first housing 551 by asecond protrusion 565 (shown in FIG. 99) about which the second housing552 is configured to rotate relative to the first housing 551. Thesecond housing 552 can be slidably coupled to the second protrusion 565such that the second housing 552 is configured to move from a firstposition (e.g., as shown in FIG. 95) to a second position (e.g., asshown in FIG. 96) along the second protrusion 565. In the firstposition, a third protrusion 566 can block rotational movement of thesecond housing 552 relative to the first housing 551 to impede distalmovement of the sensor 206 x.

The system 202 ac can comprise a release mechanism (e.g., the button 567and the components actuated by the button 567). The release mechanismcan be configured to enable the second housing 552 to rotate relative tothe first housing 551. The release mechanism can comprise a button 567and/or any suitable trigger. The first housing 551 can comprise a button567 configured to move the second housing 552 from the first position tothe second position in which the second housing 552 is configured torotate relative to the first housing 551 to move the sensor 206 xdistally.

Flex-Tornado

Applicators can be removable (e.g., can be uncoupled from a base). Insome embodiments, applicators are a permanent part of the sensor system.For example, any of the applicators described herein can be permanentlyintegrated into each system such that removing the applicators from thebase is unnecessary. Some of the applicators are illustrated as beinglarge to increase the clarity of certain features. The applicators,however, can be miniaturized such that they are not cumbersome even ifthe applicators are part of the system that the host wears for days,weeks, months, or even years.

FIGS. 60-63 illustrate an example of a system 202 t that can include anintegrated applicator. A separate, removable applicator is not necessaryin the embodiment illustrated in FIGS. 60-63. In several embodiments,the applicator is removable to minimize the size of the wearable device.

Applicators can be configured to compress distally via flexing of theapplicators. Certain portions of the applicators can be compliant toenable flexing. This flexing can enable the applicator to move a sensordistally into the skin.

FIGS. 8A-D of the following patent application illustrate applicatorembodiments configured to flex to insert the sensor into the skin: U.S.patent application Ser. No. 12/893,850; filed Sep. 29, 2010; and titledTranscutaneous Analyte Sensor. The entire contents of the followingapplication are incorporated by reference herein: U.S. patentapplication Ser. No. 12/893,850; filed Sep. 29, 2010; and titledTranscutaneous Analyte Sensor.

FIGS. 60-63 illustrate an embodiment of an applicator 475 t that cancompress distally via flexing. (Additional details regarding embodimentsillustrated in FIGS. 60-63 are explained above.)

The system 202 t can include arms 427 configured to guide a top portion(e.g., the transmitter 211 t) towards the base 204 t. The arms 427 cansupport and position the top portion as the arms 427 flex to enable thesystem 202 t to compress to move the sensor 206 t distally (e.g., intothe skin of the host). The arms 427 can be configured to guide the topportion in a linear manner towards the base 204 t or can be configuredto rotate the top portion relative to the base 204 t as the system 202 tmoves the sensor 206 t distally. The system 202 t illustrated in FIGS.60-63 can be used with or without bellows 421.

Applicators (e.g., 745 t) can comprise living hinges 423 (labeled inFIG. 61) configured to flex to enable the applicators to compress. Thiscompressive movement can drive a sensor 206 t (e.g., 206 t) into theskin of a host.

Some embodiments comprise multiple living hinges 423 located radiallyoutward from a distal portion of the sensor 206 t (e.g., as shown inFIG. 62). The living hinges 423 can be spaced apart around a perimeterof a hole 435 in the base 204 t such that the living hinges 423 areconfigured to help guide the distal portion of the sensor 206 t throughthe hole 435 and into the skin. The living hinges 423 can facilitatelinear and/or rotational movement of the proximal portion relative tothe distal portion.

The living hinges 423 can be configured to cause a proximal portion(e.g., the transmitter 211 t) of the base 204 t to rotate relative to adistal portion of the base 204 t as the proximal portion moves towardsthe distal portion.

The living hinges 423 can have a first position (e.g., a startingposition as illustrated in FIGS. 61 and 62) in which the living hinges423 hold the proximal portion in a proximal starting position such thatthe sensor 206 t is in a predeployed state (prior to user activation).The living hinges 423 can have a second position (e.g., as illustratedin FIG. 63) in which the sensor 206 t is in a deployed state and inwhich the living hinges 423 are in a flexed state.

A blocking structure (e.g., 424) can be located between the proximalportion and the distal portion to prevent the sensor 206 t from beingdeployed before the blocking structure is removed.

A base 204 t can comprise a proximal portion 442 coupled to a distalportion 441 by flex arms 427 configured to facilitate moving and guidingthe proximal portion 442 towards the distal portion 441 in response to adistal force on the proximal portion 442. Thus, the flex arms 427 canfacilitate inserting at least a portion of the sensor 206 t into theskin. The proximal portion 442 can couple the transmitter to the distalportion 441.

A base 204 t can comprise a proximal portion 442 coupled to a distalportion 441 by flex arms 427 configured to cause the proximal portion442 to rotate relative to the distal portion 441 in response to movingthe proximal portion 442 distally (relative to the distal portion 441)to insert at least a portion of the sensor 206 t into the skin.

The flex arms 427 can comprise at least one living hinge 423 thatcouples the flex arm 427 to at least one of the proximal portion 442 andthe distal portion 441 of the base 204 t. In some embodiments, theliving hinges 423 and/or the arms 427 are configured to rotate theproximal portion 442 relative to the distal portion 441 in response tomoving the sensor 206 t distally. The flex arms 427 can be spaced arounda distal end of the sensor 206 t such that the flex arms 427 areconfigured to rotate the distal end as the distal end moves from aproximal starting position (e.g., as illustrated in FIG. 62) to a distalending position (e.g., as illustrated in FIG. 63).

A removable interference member (e.g., 242 in FIG. 60) can be locatedbetween the distal portion 441 and the proximal portion 442 such thatthe removable interference member is configured to block the system 202t from moving the sensor 206 t from a proximal starting position to adistal ending position. Removing the interference member can enable thesystem 202 t to move the sensor 206 t to the distal ending position.

The base 204 t can comprise a proximal portion 442 coupled to a distalportion 441 by a first arm 427 and a second arm 427. A distal endportion of the sensor 206 t comprises a central axis. The first arm 427can be oriented at a first angle of plus or minus 45 degrees ofperpendicular to the central axis. The second arm 427 can be oriented ata second angle of plus or minus 45 degrees of perpendicular to thecentral axis.

The first and second arms 427 can be configured to guide the proximalportion 442 linearly relative to the distal portion 441 as the proximalportion 442 moves towards the distal portion 441. The first and secondarms 427 can be configured to cause the proximal portion 442 to rotaterelative to the distal portion 441 in response to moving the distal endportion of the sensor 206 t from a proximal starting position to adistal ending position.

The second arm 427 can slant away from the first arm 427 (e.g., asillustrated in FIG. 61) such that the first and second arms 427 areconfigured to rotate the distal end portion of the sensor 206 t as thesystem 202 t moves the sensor 206 t from the proximal starting positionto the distal ending position.

The system 202 t can include a mechanical interlock 429 configured toreleasably hold the bellows 421, arms, and/or a spring in a compressedstate. Releasing the mechanical interlock 429 can retract the sensor 206t from the skin such that the portion of the sensor 206 t that waslocated distally relative to the distal side 207 t of the base 204 t ismoved proximally into an interior area of the system 202 t. Theinterlock 429 can be a snap fit formed by an undercut (e.g., as shown inFIG. 63).

Hinge Applicator—Broad Version

Several embodiments use rotational movement to insert a sensor. Someembodiments rely on a hinge pivoting to insert the sensor. Rotationalmovement can enable structurally-robust, low-profile applicators thatare less intimidating to users (due to their small size).

As described above, the system 202 f illustrated in FIGS. 17-19 can beused to retract a sensor 206 f. The system 202 f, however, can also beused to insert a sensor 206 f into tissue of a host (e.g., by reducingrather than increasing a pivot angle 271 between a first portion 272 anda second portion 273). Thus, the system 202 f can insert the sensor 206f and retract the sensor 206 f. When the system 202 f is used to insertthe sensor 206 f, FIG. 19 can illustrate a proximal starting position,and FIG. 18 can illustrate a distal ending position.

The sensor system 202 f can comprise a base 204 f, a transmitter 211 f,and a distal side 207 f. A spring 275 (e.g., a helical spring, acompression spring, a tension spring, a leaf spring, a torsional spring)can be configured to decrease the pivot angle 271 (e.g., once releasedby a triggering mechanism and/or any suitable mechanism) to insert thesensor 206 f. Some embodiments do not include a spring 275, but rely ona user applying a distal force on the second portion 273 to push thesecond portion 273 towards the first portion 272.

The spring 275 can be a torsion spring, a leaf spring, a helical spring,a conical spring, a compression spring, a tension spring, an integrallymolded deforming body, a flex arm, any type of spring described herein,any type of spring incorporated by reference, and/or any suitable typeof spring.

The hinge 270 can comprise a pin 276 rotatably coupled to a sleeve 277configured to retain the pin 276 as the second portion 273 rotatesrelative to the first portion 272. The base 204 f can comprise the firstportion 272 and the second portion 273. The first portion 272 can couplethe first adhesive 210 to the second portion 273. The second portion 273can comprise the transmitter 211 f.

Pivoting the second portion 273 towards the first portion 272 can pushthe sensor 206 f out of a hole 278 in the base 204 f. Some embodimentsuse a spring 275 to pivot the hinge 270.

A detent can releasably secure the hinge 270 in a starting position suchthat pivoting the hinge 270 requires overcoming a torque threshold or aforce threshold. The detent can be built into the hinge 270. The detentcan be positioned between a first surface of the first portion 272 and asecond surface of the second portion 273.

A base 204 f can comprise a first portion 272 and a second portion 273coupled by a hinge 270 configured such that pivoting the second portion273 towards the first portion 272 causes the sensor 206 f to move from aproximal starting position (e.g., as illustrated in FIG. 19) to a distalending position (e.g., as illustrated in FIG. 18). The second portion273 can couple the transmitter 211 f to the first portion 272. The firstportion 272 can couple the adhesive 210 to the second portion 273.

The base 204 f can be configured such that decreasing a pivot angle 271between the first portion 272 and the second portion 273 moves a distalend of the sensor 206 f out of a hole 278 of the distal side 207 f ofthe base 204 f to facilitate the distal end of the sensor 206 f piercingthe skin. A proximal segment of the sensor 206 f can be coupled to thesecond portion 273 such that the system 202 f can be configured to movea portion of the sensor 206 f out of an area 283 between the firstportion 272 and the second portion 273, and then distally through thehole 278 of the base 204 f in response to decreasing the pivot angle271.

The base 204 f can comprise a left half 279 and a right half 280. Theleft half 279 can comprise the hole 278 of the base 204 f. The righthalf 280 can comprise the hinge 270 (such that the hole 278 and thehinge 270 are located on different halves of the base 204 f). The hinge270 can comprise a pin 276 rotatably coupled to a sleeve 277 configuredto retain the pin 276 as the second portion 273 rotates relative to thefirst portion 272.

Hinge Applicator—Mouse-Trap Version

Embodiments that use rotational motion to insert and/or retract a sensorcan include one, two, three, or more rotating supports (e.g., arms,bodies). FIGS. 101-106 illustrate an applicator 475 ad that comprisestwo rotating supports.

Some hinge 584 embodiments include a first body 581 (e.g., a first arm,a first support) configured to rotate in order to move the sensor 206 adand/or the base 204 ad distally (e.g., into the skin of the host).Several embodiments include a second body 582 (e.g., a second arm, asecond support) configured to rotate in order to uncouple the applicator475 ad from the base 204 ad and/or the sensor 206 ad.

FIG. 101 illustrates a perspective view of a system 202 ad with aremovable applicator 475 ad in a proximal starting position. Actuatingthe tab 596 (e.g., by pressing and/or moving the tab 596) can cause thesystem 202 ad to move the sensor 206 ad distally by rotating bodies 581,582 about a hinge 584.

FIG. 102 illustrates a side, cross-sectional view of the system 202 adin the proximal starting position. A first spring 585 (e.g., a leafspring) is in a flexed state (e.g., a high-energy state). The fifth arm595 and the tab 596 are coupled to the housing 580 to resist therotational force (i.e., a torque) of the first spring 585. Disengagingthe tab 596 enables the first spring 585 to rotate the first body 581and the second body 582 in a counter-clockwise direction about the hinge584.

A second spring 586 is in a flexed state (e.g., a high-energy state)that applies a clockwise rotational force (i.e., a torque). The secondbody 582 is secured to the first body 581 by a third arm 590 (shown inFIG. 103) that resists the clockwise rotational force of the secondspring 586 (until the third arm 590 and/or another arm that is a mirrorimage of the third arm 590 flex to disengage the second body 582 fromthe first body 581 to enable the second body 582 to rotate away from thefirst body 581).

The each spring (e.g., 585, 586) can be a torsion spring, a leaf spring,a helical spring, a conical spring, a compression spring, a tensionspring, an integrally molded deforming body, a flex arm, any type ofspring described herein, any type of spring incorporated by reference,and/or any suitable type of spring.

The applicator 475 ad can comprise a distal portion 477 ad. The hinge584 can couple the first body 581 and the second body 582 to the distalportion 477 ad of the applicator 475 ad. The base 204 ad can comprise atransmitter 211 ad.

FIG. 103 illustrates a perspective view of the system 202 ad in theproximal starting position. (The housing 580 is hidden in FIGS. 103-106to enable clear viewing of internal features.) The first body 581 andthe second body 582 can rotate about the same rotational axis (e.g., ofthe hinge 584).

FIG. 104 illustrates another perspective view of the system 202 ad inthe proximal starting position. The third arm and its opposite 590 canreach around the first body 581 such that the first body 581 is locatedat least partially between the second body 582 and the base 204 ad,which can secure the second body 582 to the first body 581.

In the state illustrated in FIG. 104, the first spring 585 (shown inFIG. 102) applies a rotational force oriented to move the base 204 adand/or the sensor 206 ad distally. The rotational force of the firstspring 585 is counter balanced due to the fifth arm 595 being coupled tothe housing 580 (e.g., as shown in FIGS. 101 and 102).

In the state illustrated in FIG. 104, the second spring 586 (shown inFIG. 102) applies a rotational force oriented to rotate the second body582 away from the first body 581. The rotational force of the secondspring 586 is counter balanced by the third arm 590 (which couples thesecond body 582 to the base 204 ad to block the second body 582 fromrotating away from the first body 581).

Uncoupling the fifth arm 595 from the housing 580 (e.g., by actuatingthe tab 596) enables the first spring 585 to rotate the first body 581,the second body 582, the base 204 ad, and the sensor 206 ad to the stateillustrated in FIG. 105. Arriving at the state illustrated in FIG. 105causes a portion of the third arm and its opposite 590 to contactdisengagement features (e.g., of the base 204 ad). The disengagementfeatures of the base 204 ad cause the third arm and its opposite 590 touncouple from the base 204 ad to uncouple the second body 582 from thefirst body 581, which enables the adhesive 210 ad to couple the base 204ad to the skin as the second body 582 rotates away from the first body581.

FIG. 106 illustrates a perspective view of the system 202 ad after thesecond body 582 has rotated away from the first body 581 and theadhesive 210 ad has coupled the base 204 ad to the skin of the host. Inthe state illustrated in FIG. 106, the applicator 475 ad is no longercoupled to the base 204 ad and the sensor 206 ad. As a result, theapplicator 475 ad can be moved proximally while leaving the base 204 adand the sensor 206 ad coupled to the skin of the host.

Referring now to FIGS. 101-106, some hinge embodiments use two armsconfigured to rotate about at least one pivot axis. The first body 581can be configured to push the sensor 206 ad from a proximal startingposition (e.g., as illustrated in FIG. 104) to a distal ending position(e.g., as illustrated in FIG. 106). The second body 582 can beconfigured to secure the base 204 ad and/or the sensor 206 ad to thefirst body 581 while the first body 581 inserts the sensor 206 ad intothe skin. The second body 582 can also release the base 204 ad and/orthe sensor 206 ad (e.g., while the first body 581 holds the sensor 206ad in the distal ending position).

Each of the bodies 581, 582 can have a spring 585, 586 (e.g., atorsional spring, a leaf spring, an integrally molded flex tab). A firstspring 585 of the first body 581 can provide energy to rotate the firstbody 581 in a first rotational direction that inserts the sensor 206 ad.A second spring 586 can provide energy that rotates the second body 582in a second rotational direction (that is opposite relative to the firstrotational direction) to release the base 204 ad from the applicator 475ad.

Thus, springs 585, 586 can be configured to facilitate pivoting a secondportion relative to a first portion. Either spring 585, 586 can be atorsional spring, integrally molded flex tab, and/or a leaf springconfigured to apply a torque about the hinge 584.

The system 202 ad can comprise a removable applicator 475 ad. Theapplicator 475 ad can comprise a housing 580; a first body 581 rotatablycoupled to the housing 580 by a hinge 584 having a hinge axis; a secondbody 582 rotatably coupled to the housing 580 about the hinge axis; afirst spring 585 configured to rotate the first body 581 in a firstrotational direction to move the sensor 206 ad from a proximal startingposition to a distal ending position; and a second spring 586 configuredto rotate the second body 582 in a second rotational direction that isopposite to the first rotational direction.

The second body 582 can be configured to couple the base 204 ad to thehousing 580 as the first body 581 rotates in the first rotationaldirection. The first body 581 can be configured to hold the sensor 206ad in the distal ending position while the second body 582 uncouples thebase by detaching a retaining feature (e.g., an undercut, an adhesive)204 ad from the applicator 475 ad by rotating in the second rotationaldirection.

The applicator 475 ad can comprise a first interlock (e.g., a firstmechanical interlock 589) that releasably couples the second body 582 tothe base 204 ad such that the first body 581 is configured to move thesecond body 582 and the base 204 ad in the first rotational direction.

The first body 581 can be located at least partially between the base204 ad and the second body 582. The first mechanical interlock 589 cancomprise a third flex arm 590 that secures the first body 581 at leastpartially between the base 204 ad and the second body 582. The firstmechanical interlock 589 can be configured to uncouple from the base 204ad to enable the second body 582 to rotate in the second rotationaldirection in response to the first body 581 moving the second body 582in the first rotational direction.

The housing 580 (or another portion of the applicator 475 ad) cancomprise a second interlock (e.g., a second mechanical interlock 591)configured to hold the first body 581 in a distal position while thesecond body 582 rotates in the second rotational direction. The secondmechanical interlock 591 can comprise a left fourth flex arm 594 and aright fourth flex arm 594 configured to couple to least a portion of thefirst body 581.

The applicator 475 ad can comprise a fifth flex arm 595 that couples thefirst body 581 (and/or the second body 582) to the housing 580 such thatthe sensor 206 ad is in the proximal starting position. The fifth flexarm 595 can be configured to resist a rotational force of the firstspring 585. A portion of the fifth flex arm 595 can protrude through achannel of the housing 580. The channel can couple (e.g., connect and beoriented between) an interior of the housing 580 and an exterior of thehousing 580.

A portion of the fifth flex arm 595 can protrude from an exterior of thehousing 580 such that the portion comprises an actuation tab 596 and/oran actuation lever. The fifth flex arm 595 can be configured to uncouplefrom the housing 580 to enable the first body 581 to rotate in responseto moving the actuation tab 596 and/or the actuation lever. The fifthflex arm 595 may be actuated and/or triggered by an electronic, moving,translating, and/or sliding user activation button.

Any of the features described in the context of FIGS. 85-106 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 85-106 can becombined with the embodiments described in the context of FIGS. 1-84 and107-126. Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way (e.g., one, two, three, or more embodiments may be combinable inwhole or in part). Further, any of the features of an embodiment may bemade optional to other aspects or embodiments. Any aspect or embodimentof a method can be performed by a system or apparatus of another aspector embodiment, and any aspect or embodiment of a system can beconfigured to perform a method of another aspect or embodiment.

Sensors

Many embodiments described herein comprise a sensor (e.g., atranscutaneous analyte measurement sensor). Many sensor features aredescribed below. Each of the sensor embodiments can be used with and/orin the place of each of the sensors described in the context of FIGS.1-106, other locations herein, and/or as incorporated by reference. Toavoid unnecessary redundancy to and facilitate focusing on sensordetails, many sensor features are not described for each embodiment, butinstead are described below to enable the reader to understand the manysensor features that can be used with and/or in the place of each of thesensors described in the context of FIGS. 1-106, in other locationsherein, and/or as incorporated by reference.

Patients sometimes feel pain when a distal portion of the sensor isinserted into the skin. Thus, in some cases there is a need for systemsand methods that minimize or even eliminate this pain. A distal tip ofthe sensor should be sharp enough to easily pierce the skin (e.g., havea low insertion force), which minimizes the discomfort patients feel.

The sensor can include a membrane coating. The membrane can cover asharp distal tip. The sharp distal tip can cause the sensor membrane todelaminate (e.g., shear off) during insertion of the distal tip into theskin or during in vivo use of the sensor. Preventing membrane breechingand maintaining the adhesion between the membrane and the distal tip canbe very difficult. Decreasing the sharpness of the distal tip allows formore robust membrane adhesion but introduces other disadvantages such aspain, higher insertion forces, sensor deployment failure, and inaccuratesensor data (due to the tissue trauma).

Thus, in some cases there is a need for systems and methods thatminimize patient pain (e.g., by being sharp) while also minimizingtissue trauma and preventing membrane delamination. Many unique sensortip shapes described herein can accomplish all of these seeminglyincompatible and conflicting goals.

Sensors can be at least partially coated by a membrane. The followingpatent application includes membrane details: U.S. patent application14/250,320; filed Apr. 10, 2014; and entitled Sensors for ContinuousAnalyte Monitoring and Related Methods. The entire contents of U.S.patent application Ser. No. 14/250,320 are incorporated by referenceherein.

Some embodiments include novel geometries that enable low insertionforces and minimal tissue trauma while guarding against membranedelamination. Reducing the sharpness of the distal tip of the sensor canreduce the likelihood of piercing cellular walls. Reducing the sharpnessof the distal tip can reduce the immune response by pushing cells out ofthe way of the sensor insertion path rather than cutting cells and/orpiercing cells.

When a sensor is inserted into tissue, the force necessary to insert thesensor into the tissue can be measured. An insertion force peak can beidentified each time a sensor is inserted into tissue (e.g., synthetictissue, human tissue). FIG. 107 illustrates peak insertion forces offour sensors. The shape of each of the sensors is illustrated in FIG.107. A first sensor tip 601 has a first peak insertion force indicatedby a first bar 602. A second sensor tip 603 has a second peak insertionforce indicated by a second bar 604. A third sensor tip 605 has a thirdpeak insertion force indicated by a third bar 606. A fourth sensor tip607 has a fourth peak insertion force indicated by a fourth bar 608.

The fourth sensor tip 607 was made by forming a tube and then removingan end portion of the tube at an angle to create a bevel needle (with ahollow interior and a hole in a distal portion). The other sensor tips601, 603, 605 do not include a hollow interior and a hole in a distalportion.

The first three sensors 601, 603, 605 enable dramatically lowerinsertion forces than the fourth sensor 607. The first sensor 601,however, has a sharp distal tip that often results in delamination of amembrane that coats the first sensor 601. This delamination canjeopardize the ability of the sensor system to accurately analyzeanalyte indications.

FIG. 108 illustrates the first sensor 601 in a first state prior tobeing coated by a membrane. FIG. 109 illustrates the first sensor 601 aafter being coated by a membrane and then being cycled one hundred timeswithin tissue. A first portion 610 of the sensor 601 a is coated by themembrane. The membrane has delaminated from a second portion 611 of thesensor 601 a.

FIG. 110 illustrates the second sensor 603 in a first state prior tobeing coated by a membrane. FIG. 111 illustrates the second sensor 603 aafter being coated by a membrane and then being cycled 100 times withintissue. As shown in FIG. 111, the membrane has not delaminated due tothe unique shape of the distal tip of the sensor 603 a. The third sensor605 also effectively resists delamination of the membrane. Thus, thesecond sensor 603 a and the third sensor 605 provide far superiormembrane delamination resistance than the first sensor 601 a while stillachieving far lower insertion forces than the fourth sensor 607.Additional details are described below regarding specific geometriesthat enable these benefits.

Parabolic Tip

FIG. 112 illustrates a side view of sensors 614-618. FIG. 113illustrates a bottom view of the sensors 614-618. FIG. 114 illustrates aperspective view of the sensors 614-618. The proximal portions of thesensors 614-618 are hidden in FIGS. 112-114.

The first sensor 614 and the second sensor 615 have a distal end portionwith a parabolic shape. A slope of the parabolic distal end portion cancomprise a linear derivative. Parabolic shapes can be well-suited toresisting membrane delamination while facilitating low insertion forces.

The maximum width of the parabolic shape can be at least 50 percent ofthe maximum width of a distal portion of the sensor configured to beinserted into the skin. In some embodiments, the maximum width of theparabolic shape can be at least 60 percent, at least 80 percent, 100percent, less than 90 percent, and/or less than 100 percent of themaximum width of the distal portion of the sensor configured to beinserted into the skin.

A parabolic shape allows for approximately uniform membrane coating ofthe distal end portion of the sensor. A parabolic shape, however, can beexpensive and difficult to manufacture in a repeatable fashion. Theparabolic distal end portion can be formed by grinding, electricaldischarge machining (“EDM”), laser cutting, and/or laser ablation of thedistal end portion, but achieving a precise profile can be difficult.

FIG. 115 illustrates a side view of a distal portion of a sensor 615.The sensor 615 comprises a distal end portion 620 having a central axis621 and a planar profile coincident with the central axis 621. Theplanar profile of the distal end portion 620 can be parabolic (e.g., asillustrated in FIG. 115).

In some embodiments, the distal end portion 620 of the sensor 615 iscoated with a membrane 622. A distal tip 623 of the sensor 615 can beconfigured to pierce the skin and can be rounded to resist delaminationof the membrane 622.

In several embodiments, the distal end portion 620 of the sensor 615 iscoated with a membrane 622. The parabolic distal end portion 620 can beconfigured to provide a gradual diameter increase to reduce tissuetrauma and to provide a curved distal tip 623 configured to resistdelamination of the membrane 622.

In some embodiments, a segment of the sensor 615 is configured to beinserted into the skin. The segment can comprise a first maximum width625. The parabolic distal end portion 620 can comprise a second maximumwidth 626 that is at least 50 percent of the first maximum width.

In several embodiments, the distal end portion 620 is coated by amembrane 622 configured to enable the sensor 615 system to measure aglucose indication. The membrane 622 can comprise a thickness thatvaries by less than plus or minus 30 percent relative to an averagethickness of the membrane 622.

In some embodiments, the parabolic distal end portion 620 comprises adistal section and a proximal section. The distal section can comprise afirst angle relative to the central axis 621. (The first angle can bemeasured between line 627 and the central axis 621.) The proximalsection can comprise a second angle relative to the central axis 621.(The second angle can be measured between line 628 and the central axis621.) The first angle can be at least twice as large as the second anglesuch that the first angle is configured to resist delamination of themembrane 622 and the second angle is configured to gradually increase awidth of the profile.

In several embodiments, the sensor 615 comprises a distal end portion620 having a central axis 621 and a planar profile coincident with thecentral axis 621. A distal tip 623 of the sensor 615 can be curved suchthat the planar profile comprises a curved distal end 630 that couples afirst curved side 631 to a second curved side 632.

In some embodiments, the distal end portion 620 of the sensor 615 iscoated with a membrane 622. The curved distal end can be configured toresist delamination of the membrane 622. The first curved side 631 andthe second curved side 632 can be configured to provide a smoothtransition from the distal tip 623 to resist delamination and to providea gradual transition from a first diameter of the distal tip 623 to amaximum diameter 626 of the distal end portion 620.

Blunted Tip

FIGS. 112-114 illustrate a sensor 616 with a shape that is relativelyeasy to manufacture. The profile of the distal end portion 638 of thesensor 616 has straight sides coupled by a parabolic and/or roundeddistal tip 637. The straight sides enable low insertion forces while therounded distal tip 637 resists membrane 639 delamination.

The distal end portion 638 of the sensor 616 can be manufactured byforming a conical shape and then grinding (e.g., with abrasive disks)the distal tip 637 until the end of the distal tip 637 comprises aparabolic and/or rounded shape. This embodiment can be much easier andmore repeatable to manufacture while (a) having a low insertion forceand (b) resisting membrane 639 delamination.

Membrane 639 delamination typically starts at the distal tip 637 andpropagates proximally along the sensor 616. The blunted tip provides asubstantial surface oriented at a large angle relative to the insertiondirection (e.g., as indicated by distal arrow 209). This surfacegeometry resists membrane 639 delamination at the distal tip 637 becauseinserting the distal tip 637 into the skin places the membrane 639 thatcovers the distal tip 637 in a compressed state (rather than in a shearstate). The blunted tip also resists membrane 639 delamination bydramatically lowering the stress concentration on the distal tip 637(compared to a more pointed tip). Stress can be approximated as forcedivided by area. As the area approaches zero, the local stress on thetip becomes infinite. Increasing the area reduces the stress. Resistingmembrane 639 delamination at the tip also precludes delamination fromspreading proximally along the sensor 616 by preventing the initiationof delamination.

FIG. 116 illustrates a side view of a distal portion of a sensor 616.The distal portion of the sensor 616 comprises a central axis 634 and aprofile (defined by the central axis 634). The profile can comprisestraight sides 635, 636 and a rounded distal tip 637. The straight sides635, 636 (of the profile taken along a central axis 634 of the distaltip 637) result in a shape with very little insertion resistance andthus provide a low insertion force.

In some embodiments, the sides 635, 636 are rounded and the distal tip637 is parabolic. The parabolic tip provides a very small angle betweena direction of insertion (e.g., as indicated by distal arrow 209) and asurface to which the membrane 639 is adhered. As a result, the distaltip 637 provides robust delamination resistance.

The radius of the distal tip 637, the latus rectum of the parabola ofthe distal tip 637, and/or the maximum width of the parabola of thedistal tip 637 can be 25 plus or minus 10 micrometers. The angle betweenthe straight sides 635, 636 of the profile can be 20 degrees plus orminus 5 degrees.

The sensor 616 can comprise a distal end portion 638 that is conicalwith a rounded distal tip 637. The rounded distal tip 637 can beconfigured to resist delamination of a membrane 639 that coats thedistal end portion 638. The distal end portion 638 can be conical tofacilitate piercing the skin.

The sensor 616 can comprise a distal end portion 638 that is conicalwith a blunted distal tip 637. The blunted distal tip 637 can beconfigured to resist delamination of a membrane 639 that coats thedistal end portion 638.

The sensor 616 can comprise a distal end portion 638 having a centralaxis 634 and a planar profile coincident with the central axis 634. Adistal tip 637 of the sensor 616 can be curved such that the planarprofile comprises a curved distal end that couples a first straight side635 to a second straight side 636.

In some embodiments, the distal end portion 638 can be coated by amembrane 639. The distal tip 637 can be curved such that the distal tip637 is configured to resist delamination of the membrane 639. The firstand second sides 635, 636 can be straight such that the sides 635, 636are configured to linearly increase a diameter of the distal end portion638 to reduce tissue trauma caused by inserting the distal end portion638 into the skin.

In several embodiments, the curved distal end comprises a radius that isgreater than 10 micrometers and less than 35 micrometers such that thecurved distal end is configured to be large enough to resistdelamination of a membrane 639 that coats the curved distal end andsmall enough to reduce patient discomfort associated with piercing ofthe skin.

In some embodiments, the curved distal end comprises a maximum widththat is greater than 10 micrometers and less than 35 micrometers suchthat the curved distal end is configured to be large enough to resistdelamination of a membrane 639 that coats the curved distal end andsmall enough to reduce patient discomfort associated with piercing ofthe skin. An angle between the first and second straight sides 635, 636can be greater than 15 degrees and less than 25 degrees such that theangle is configured to reduce patient discomfort associated withpiercing of the skin.

Dual-Angle Tip

FIGS. 112-114 illustrate sensors 617, 618 that include dual-angle distalend portions. The sensors 617, 618 each have a profile that includes twoangles. The second angle can be larger (relative to a central axis) thanthe first angle. A first sensor 617 comprises a sharp distal tip. Asecond sensor 618 comprises a rounded distal tip to resist membranedelamination.

FIG. 117 illustrates a side view of a distal portion 642 of a sensor618. The distal portion 642 of the sensor 618 comprises a central axis646 and a profile (defined by the central axis 646). The sides 643, 650,645, 651 of the profile comprise a first angle (relative to the centralaxis 646) and a second angle (relative to the central axis 646). Thesecond angle can be larger than the first angle such that the secondangle is configured to resist membrane 647 delamination and the firstangle is configured to provide a gradual diameter increase.

The sensor 618 can comprise a distal end portion 642 having a centralaxis 646 and a planar profile coincident with the central axis 646. Theplanar profile can comprise a left portion having a first side 643coupled to a second side 650. The planar profile can comprise a rightportion having a third side 645 coupled to a fourth side 651. A firstangle between the first side 643 and the third side 6445 can be smallerthan a second angle between the second side 650 and the fourth side 651such that a proximal section 648 of the end portion 642 provides a moregradual width increase than a distal section 649 of the end portion 642.The first, second, third, and fourth sides 643, 650, 645, 651 can bestraight. The first, second, third, and fourth sides 643, 650, 645, 651can be curved.

A curved distal end 644 can couple the second side 650 to the fourthside 651. The curved distal end 644 can be configured to resistdelamination of a membrane 647 that coats the distal end portion 642 ofthe sensor 618.

The sensor 618 can be a glucose sensor 618 comprising a membrane 647that coats the distal end portion 642 of the sensor 618. The distal endportion 642 can be configured to resist delamination of the membrane647, reduce tissue trauma, and/or reduce patient discomfort caused bypiercing the skin.

Faceted Tips

Any of the sensors described herein can be faceted (e.g., with one, two,three, four, five, or more facets). The distal tips of the facetedembodiments can be rounded to achieve the membrane delaminationresistance described above.

Each of the sensors 653-660 illustrated in FIGS. 118-120 are faceted.Each facet can be formed by a planar grinding process. Faceted tipsenable repeatable manufacturability, enable a relatively small (yetrounded) distal tip, and provide a gradual transition from the distaltip to a maximum diameter of the sensor.

The facets can be flat or curved surfaces that intersect with adjacentfacets. The intersection between facets can form a ridge. The ridge canbe rounded to reduce tissue trauma and to increase membrane delaminationresistance.

FIG. 118 illustrates a side view of sensors 653-660. FIG. 119illustrates a bottom view of the sensors 653-660. FIG. 120 illustrates aperspective view of the sensors 653-660. The proximal portions of thesensors 653-660 are hidden in FIGS. 118-120.

A first sensor 653 has one facet. A second sensor 654 also has onefacet, but also includes a rounded ridge 661. A third sensor 655 and afourth sensor 656 each have two facets, but the fourth sensor 656 alsoincludes a rounded distal tip and rounded ridges. A fifth sensor 657 anda sixth sensor 658 each have three facets, but the sixth sensor 658 alsoincludes a rounded distal tip and rounded ridges. A seventh sensor 659and an eighth sensor 660 each have four facets, but the eighth sensor660 also includes a rounded distal tip and rounded ridges.

FIG. 121 illustrates a bottom view of a sensor 660 that comprises fourfacets 667, 668, 669, 670. FIG. 122 illustrates a first perspective viewof the sensor 660. FIG. 123 illustrates a second perspective view of thesensor 660. A proximal portion of the sensor 660 is hidden in FIGS.121-123.

In some embodiments, the sensor 660 comprises a distal end portion 671having a central axis and a first facet 667 oriented at a first angle ofless than 25 degrees relative to the central axis such that the firstfacet 667 is configured to facilitate piercing the skin. The distal endportion 671 of the sensor 660 can comprise a second facet 668 orientedat a second angle of less than 25 degrees relative to the central axis.The first facet 667 can be oriented at a third angle relative to thesecond facet 668. The third angle can be greater than 10 degrees andless than 25 degrees.

In several embodiments, the first facet 667 and a second facet (e.g.,669) form a wedge configured to facilitate piercing the skin. The distalend portion 671 of the sensor 660 can be coated by a membrane 673. Arounded ridge 674 can couple the first facet 667 to the second facet 668such that the rounded ridge 674 is configured to resist delamination ofthe membrane 673.

In some embodiments, the distal end portion 671 of the sensor 660comprises a third facet 669 oriented at a fourth angle of less than 25degrees relative to the central axis. The first, second, and thirdfacets can form a triangular pyramid configured to facilitate piercingthe skin. The distal end portion 671 of the sensor 660 can be coated bya membrane 673. The triangular pyramid can comprise a rounded distal tipconfigured to resist delamination of the membrane 673.

In several embodiments, a first rounded ridge 674 couples the firstfacet 667 to the second facet 668. A second rounded ridge 675 can couplethe second facet 668 to the third facet 669. The first rounded ridge 674and the second rounded ridge 675 can be configured to reduce tissuetrauma caused by inserting the distal end portion 671 of the sensor 660into the host.

In some embodiments, the distal end portion 671 of the sensor 660comprises a fourth facet 670 oriented at a fifth angle of less than 25degrees relative to the central axis. The first, second, third, andfourth facets 667, 668, 669, 670 can form a rectangular pyramidconfigured to facilitate piercing the skin of the host.

Stepped Tips

The distal tip of a sensor can include one or more steps to provide asurface that is approximately perpendicular to a central axis of thedistal tip. This perpendicular surface can provide robust membranedelamination protection. Even if membrane delamination occurs at thedistal end, the perpendicular surface can stop the proximal spread ofthe delamination. The perpendicular surface can be formed by a distalend of the insulation and/or by creating a step in the conductive core(e.g., a wire) of the sensor.

In some embodiments, the step surface is within plus or minus 35 degreesof being perpendicular to the central axis of the sensor. The stepsurface can be located distally relative to a gap located betweenproximal insulation and distal insulation.

The distal end of the sensor can have any of the shapes described hereinand/or incorporated by reference. The distal end of the sensor can bebeveled, faceted, curved, and/or parabolic.

FIG. 124 illustrates a side view of a sensor 681. FIG. 125 illustrates across-sectional view along line 125-125 from FIG. 124. The dimensions ofsome features have been exaggerated in FIGS. 124 and 125 to increase theclarity of certain features. A proximal portion of the sensor 681 ishidden in FIGS. 124 and 125.

Referring now to FIGS. 124 and 125, the sensor 681 can comprise atapered end section 685 coated by a membrane 683. The tapered endsection 685 comprises the distal tip 686 of the sensor 681. The taperedend section 685 can comprise a first step 701 configured to resistproximal movement of the membrane relative to the first step 701.

In the orientation illustrated in FIGS. 124 and 125, the tapered endsection 685 faces downward such that the tapered end portion comprisessurfaces that expand a hole in the tissue until the hole is large enoughto permit the sensor 681 to enter the tissue.

Moving along the sensor 681 in a proximal direction 208, the tapered endsection 685 increases in diameter from the distal tip 686 such that thetapered section transitions the sensor 681 from a relatively narrowdistal tip 686 to a section 687 that has a larger diameter.

Moving along the sensor 681 in a distal direction 209, the tapered endsection 685 makes a distal end portion 682 of the sensor 681progressively narrowed towards the distal tip 686.

The sensor 681 can comprise a tapered end section 685 coated by amembrane. The tapered end section 685 comprises the distal tip 686. Thesensor 681 can comprise a second step 702 located within plus or minus 1millimeter and/or within plus or minus 2.1 millimeters of the taperedend section 685. The second step 702 can be configured to resistproximal movement of the membrane relative to the second step 702. Thesecond step 702 can be formed by insulation 692 b that at leastpartially surrounds a conductive core 690.

The sensor 681 can be coated by a membrane and can comprise a first step701. The sensor 681 can comprise a groove 688 configured to be insertedinto tissue of the host. As illustrated in FIGS. 124 and 125, the groove688 is narrower (e.g., has a smaller diameter) than an adjacent proximalsection and an adjacent distal section. The groove 688 can be locatedwithin 1 millimeter, 3 millimeters, 6 millimeters, and/or 8 millimetersof the distal tip 686 of the sensor 681. The groove 688 can be locateddistally relative to the base (e.g., when the base is coupled to theskin of the host). The first step 701 and/or the second step 702 can belocated distally relative to the groove 688. The first step 701 and/orthe second step 702 can be configured to resist proximal movement of themembrane relative to the first step 701 and/or the second step 702.

The sensor 681 can comprise a conductive distal end portion 689 coatedby a membrane 683. The conductive distal end portion 689 can comprise afirst step 701 configured to resist proximal movement of the membrane683 relative to the first step 701. The conductive distal end portion689 can be made of a conductive metal. The distal end portion 682 caninclude the conductive distal end portion 689 and other features (e.g.,insulation, a membrane).

The sensor 681 can comprise a portion coated by a membrane 683. Theportion of the sensor 681 can comprise a first conductive layer 690electrically insulated from a second conductive layer 691 by aninsulation layer 692 a. The first conductive layer 690 can be configuredto be electrically coupled to the second conductive layer 691 via tissueof the host. The first conductive layer 690 can extend farther distallythan the second conductive layer 691. The first conductive layer 690 cancomprise a first step 701 configured to resist proximal movement of themembrane 683 relative to the first step 701. The first step 701 can belocated farther distally than the second conductive layer 691.

A distal portion of the sensor 681 can comprise a first step 701, asecond step 702, and/or a third step 703. The third step 703 can belocated proximally relative to the groove 688 and/or at a proximal endof the groove 688. The second step 702 and/or the third step 703 can bespaced proximally relative to the first step 701. The distal portion ofthe sensor 681 can be coated by a membrane 683. The first step 701, thesecond step 702, and the third step 703 can face distally. The steps701, 702, 703 can be configured to resist proximal movement of themembrane 683.

The steps 701, 702, 703 can each comprise a surface oriented within plusor minus 25 degrees of perpendicular to a central axis of the portion ofthe sensor 681. The steps 701, 702, 703 can each comprise a surfaceoriented within plus or minus 15 degrees of perpendicular to a centralaxis of the portion of the sensor 681. The surface can form aninterference feature configured to impede proximal movement of themembrane 683 relative to the surface by causing a compressive forcewithin the membrane 683 in response to the proximal movement of themembrane 683.

The sensor 681 can comprise a first conductive layer 690 electricallyinsulated from a second conductive layer 691 by an insulation layer 692a. The first conductive layer 690 can be conductively coupled to theconductive distal end portion 689 such that the conductive distal endportion 689 is configured to be conductively coupled to the secondconductive layer 691 via tissue of the host.

A sensor 681 can comprise a distal end portion 682 coated by a membrane683. The distal end portion 682 can comprise a gap 697 between aconductive core 690 and a conductive layer 691 of the sensor 681. Thegap 697 can be configured to enable a subcutaneous current between theconductive core 690 and the conductive layer 691. The distal end portion682 can comprise a step (e.g., 701, 702) located distally relative tothe gap 697 and configured to resist proximal movement of the membrane683 relative to the step.

The step can comprise a surface oriented within plus or minus 25 degreesof perpendicular to a central axis of the distal end portion 682. Thesurface can form an interference feature configured to impede proximalmovement of the membrane 683 relative to the surface by causing acompressive force within the membrane 683 in response to the proximalmovement of the membrane 683 relative to the distal tip 686 and/or thestep. The conductive core 690 can comprise the step (e.g., step 701). Aninsulation layer 692 b located around the conductive core 690 can formthe step (e.g., step 702).

The distal end portion 682 can comprise at least one of a rounded distaltip, a parabolic shape, a conical shape, a wedge shape, a triangularpyramid shape, a rectangular pyramid shape, and/or any of the shapesdescribed in the context of FIGS. 112-123 such that the distal endportion 682 is configured to facilitate piercing the skin.

The sensor 681 can comprise a distal end portion 682 coated by amembrane 683. The distal end portion 682 of the sensor 681 can comprisea central axis, a distal tip 686, and a distally facing surface (e.g.,step 701, step 702) spaced proximally apart from the distal tip 686. Thedistally facing surface can form a mechanical interlock with themembrane 683 such that the mechanical interlock is configured to impedeproximal movement of the membrane 683 relative to the distally facingsurface.

As used herein, the term “mechanical interlock” is used broadly. In someembodiments, a mechanical interlock can comprise two parts coupled suchthat the motion of a first part relative to a second part can cause thefirst part to compress (and/or experience a compressive force withoutcompressive movement) due to the position of the second part. As aresult, the motion of the first part is constrained by the second part.As used herein, in some embodiments, a mechanical interlock can comprisea releasable locking feature such as a snap fit formed by a flex armcoupled to an undercut, a hole, or another feature configured to atleast temporarily impede movement.

The sensor 681 can comprise a conductive core 690, a conductive layer,and an insulation layer 692 a configured to electrically insulate theconductive core 690 from the conductive layer. The conductive core 690can extend farther distally than the insulation layer 692 a to form ashortest conduction path between the conductive core 690 and theconductive layer. The distally facing surface can be located distallyrelative to the shortest conduction path (e.g., such that the third step703 is not the distally facing surface, but another step 701, 702comprises the distally facing surface).

As used herein, “extends” means to continue in a specified direction orover a specified distance, but unless stated otherwise, typically doesnot mean to become longer.

The sensor 681 can comprise a conductive core 690 and a conductive layer691 configured to enable the system (e.g., any of the systems describedherein and/or incorporated by reference) to apply a voltage between theconductive core 690 and the conductive layer 691 to measure an analyteindication. The sensor 681 can comprise a first electrical insulationlayer 692 a located around a first section of the conductive core 690and a second electrical insulation layer 692 b located around a secondsection of the conductive core 690.

The conductive layer 691 can be located radially outward from the firstinsulation layer 692 a. The first insulation layer 692 a can be spacedapart from the second insulation layer 692 b to form a gap 697configured to enable the system to apply the voltage between theconductive core 690 and the conductive layer 691. The distally facingsurface (e.g., 701, 702) can be located distally relative to the gap697. The distally facing surface can be oriented within a range of plusor minus 20 degrees relative to perpendicular to the central axis of thedistal end portion 682 of the sensor 681.

Can Apply to All Sensor Embodiments

In several embodiments, the sensor is a glucose sensor having aconductive core and a conductive layer configured to enable the systemto apply a voltage between the conductive core and the conductive layerto measure a glucose indication.

In some embodiments, the sensor comprises a first electrical insulationlayer located around a first section of the conductive core. The sensorcan comprise a second electrical insulation layer located around asecond section of the conductive core. The conductive layer can belocated radially outward from the first insulation layer. The firstinsulation layer can be spaced apart from the second insulation layer toform a gap configured to enable the system to apply the voltage betweenthe conductive core and the conductive layer. The sensor can comprise anelectrical insulation cap that covers a distal end of the conductivecore.

Any of the sensors described herein can be coated by a membrane. Themembrane can be a composite membrane that comprises two or more layers.The membrane can include an enzyme layer and a resistance layer. Themembrane can also include an interferent layer and/or an under layer. Insome embodiments, the membrane thickness can be approximately 12 to 20micrometers.

The sensor can be coated by a membrane such that the membrane forms anapproximately uniform outer layer. The membrane layer can have anaverage thickness. The membrane layer's thickness (e.g., of the taperedend section, of a section from a distal tip to an insulation layer, of adistal portion, of a section that is 3 millimeters long as measuredalong the central axis of the sensor from the distal tip) can vary byless than plus or minus 30 percent, less than plus or minus 40 percent,and/or less than plus or minus 50 percent relative to the averagethickness of the membrane. As noted above, the following patentapplication includes membrane details: U.S. patent application Ser. No.14/250,320. The entire contents of the following application areincorporated by reference herein: U.S. patent application Ser. No.14/250,320; filed Apr. 10, 2014; and titled Sensors for ContinuousAnalyte Monitoring, and Related Methods.

Any of the sensors described herein can comprise one or more electricalinsulation layers. A section of the sensor can comprise a conductivecore within one or more insulation layers configured to electricallyinsulate the section from subcutaneous body fluid (e.g., blood) of thehost. The insulation layer can be planar, tubular, and/or any suitableshape.

Any of the sensors described herein can comprise a distal end portionthat has a conductive core that is electrically insulated by anelectrical insulation cap 706. Referring now to FIG. 125, the insulationcap 706 can be at least partially covered by a membrane 683. Theinsulation cap 706 can have any suitable shape.

The insulation cap 706 can be coupled and/or attached to the insulationlayer 692 b such that an interface between the insulation cap 706 andthe insulation layer 692 b electrically insulates a distal end portionof the conductive core 690.

The insulation cap 706 can be a chemical cap 706 that electricallyinsulates the distal tip 686 of the sensor 681. The insulation cap 706can be made of adhesive, cyanoacrylate, epoxy, thermoplastic, thermoset,polyurethane, silicone, thermoplastic silicone polycarbonate urethane,thermoplastic, polycarbonate-urethane, acrylonitrile butadiene styrene,polyvinyl chloride, and/or any suitable electrically insulatingmaterial.

Any of the systems described herein can apply a fixed voltage betweenthe conductive core 690 (e.g., a wire, a conductive layer) and aconductive layer 691 located radially outward relative to the conductivecore 690. Analyte measurements can include measuring the current betweenthe conductive core 690 and the conductive layer 691. Analytemeasurements can also include other procedures and types ofmeasurements.

In some embodiments, the sensor is a glucose sensor having a conductiveportion 690 at least partially covered by a first electrical insulationlayer 692 a. The first electrical insulation layer 692 a can be at leastpartially covered by a conductive layer 691. The conductive portion 690can have a distal tip located farther distally than a distal end of theconductive layer 691. Tissue and/or fluid of the host can electricallycouple the distal tip of the conductive portion 690 to the conductivelayer 691 to enable the system to apply a voltage between the conductiveportion 690 and the conductive layer 691 such that the system canmeasure a current indicative of glucose between the conductive portion690 and the conductive layer 691. The system can use electrochemicalreactions to facilitate analyte measurements.

In some embodiments, the sensor is a glucose sensor having a conductivecore 690 at least partially covered by a first electrical insulationlayer 692 a and a second electrical insulation layer 692 b. (In severalembodiments, the distal end of the conductive core 690 is covered byinsulation 706.) The first electrical insulation layer 692 a can be atleast partially covered by a conductive layer 691. A gap (e.g., in theregion of the groove 688) between the first electrical insulation layer692 a and the second electrical insulation layer 692 b can enable thesystem to apply a voltage between the conductive core 690 and theconductive layer 691 such that the system can measure a currentindicative of glucose between the conductive core 690 and the conductivelayer 691. An assembly (comprising the conductive core 690, the firstelectrical insulation layer 692 a and the second electrical insulationlayer 692 b, and/or the conductive layer 691) can be coated by amembrane 683 such that the membrane 683 covers the gap.

Any of the features described in the context of FIGS. 107-126 can beapplicable to all aspects and embodiments identified herein. Forexample, the embodiments described in the context of FIGS. 107-126 canbe combined with the embodiments described in the context of FIGS.1-106. Moreover, any of the features of an embodiment is independentlycombinable, partly or wholly with other embodiments described herein inany way (e.g., one, two, three, or more embodiments may be combinable inwhole or in part). Further, any of the features of an embodiment may bemade optional to other aspects or embodiments. Any aspect or embodimentof a method can be performed by a system or apparatus of another aspector embodiment, and any aspect or embodiment of a system can beconfigured to perform a method of another aspect or embodiment.

Interpretation

None of the steps described herein is essential or indispensable. Any ofthe steps can be adjusted or modified. Other or additional steps can beused. Any portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in one embodiment, flowchart, orexample in this specification can be combined or used with or instead ofany other portion of any of the steps, processes, structures, and/ordevices disclosed or illustrated in a different embodiment, flowchart,or example. The embodiments and examples provided herein are notintended to be discrete and separate from each other.

The section headings and subheadings provided herein are nonlimiting.The section headings and subheadings do not represent or limit the fullscope of the embodiments described in the sections to which the headingsand subheadings pertain. For example, a section titled “Topic 1” mayinclude embodiments that do not pertain to Topic 1 and embodimentsdescribed in other sections may apply to and be combined withembodiments described within the “Topic 1” section.

Some of the devices, systems, embodiments, and processes use computers.Each of the routines, processes, methods, and algorithms described inthe preceding sections may be embodied in, and fully or partiallyautomated by, code modules executed by one or more computers, computerprocessors, or machines configured to execute computer instructions. Thecode modules may be stored on any type of non-transitorycomputer-readable storage medium or tangible computer storage device,such as hard drives, solid state memory, flash memory, optical disc,and/or the like. The processes and algorithms may be implementedpartially or wholly in application-specific circuitry. The results ofthe disclosed processes and process steps may be stored, persistently orotherwise, in any type of non-transitory computer storage such as, forexample, volatile or non-volatile storage.

Any of the features of each embodiment is applicable to all aspects andembodiments identified herein. Moreover, any of the features of anembodiment is independently combinable, partly or wholly with otherembodiments described herein in any way (e.g., one, two, three, or moreembodiments may be combinable in whole or in part). Further, any of thefeatures of an embodiment may be made optional to other aspects orembodiments. Any aspect or embodiment of a method can be performed by asystem or apparatus of another aspect or embodiment, and any aspect orembodiment of a system can be configured to perform a method of anotheraspect or embodiment.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure. In addition, certain method, event, state,or process blocks may be omitted in some implementations. The methods,steps, and processes described herein are also not limited to anyparticular sequence, and the blocks, steps, or states relating theretocan be performed in other sequences that are appropriate.

For example, described tasks or events may be performed in an orderother than the order specifically disclosed. Multiple steps may becombined in a single block or state. The example tasks or events may beperformed in serial, in parallel, or in some other manner. Tasks orevents may be added to or removed from the disclosed exampleembodiments. The example systems and components described herein may beconfigured differently than described. For example, elements may beadded to, removed from, or rearranged compared to the disclosed exampleembodiments.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list. Conjunctivelanguage such as the phrase “at least one of X, Y, and Z,” unlessspecifically stated otherwise, is otherwise understood with the contextas used in general to convey that an item, term, etc. may be either X,Y, or Z. Thus, such conjunctive language is not generally intended toimply that certain embodiments require at least one of X, at least oneof Y, and at least one of Z to be present.

The term “and/or” means that “and” applies to some embodiments and “or”applies to some embodiments. Thus, A, B, and/or C can be replaced withA, B, and C written in one sentence and A, B, or C written in anothersentence. A, B, and/or C means that some embodiments can include A andB, some embodiments can include A and C, some embodiments can include Band C, some embodiments can only include A, some embodiments can includeonly B, some embodiments can include only C, and some embodiments caninclude A, B, and C. The term “and/or” is used to avoid unnecessaryredundancy.

While certain example embodiments have been described, these embodimentshave been presented by way of example only, and are not intended tolimit the scope of the inventions disclosed herein. Thus, nothing in theforegoing description is intended to imply that any particular feature,characteristic, step, module, or block is necessary or indispensable.Indeed, the novel methods and systems described herein may be embodiedin a variety of other forms; furthermore, various omissions,substitutions, and changes in the form of the methods and systemsdescribed herein may be made without departing from the spirit of theinventions disclosed herein.

For ease of explanation and illustration, in some instances the detaileddescription describes exemplary systems and methods in terms of acontinuous glucose monitoring environment; however it should beunderstood that the scope of the invention is not limited to thatparticular environment, and that one skilled in the art will appreciatethat the systems and methods described herein can be embodied in variousforms. Accordingly any structural and/or functional details disclosedherein are not to be interpreted as limiting the systems and methods,but rather are provided as attributes of a representative embodimentand/or arrangement for teaching one skilled in the art one or more waysto implement the systems and methods, which may be advantageous in othercontexts.

For example, and without limitation, described monitoring systems andmethods may include sensors that measure the concentration of one ormore analytes (for instance glucose, lactate, potassium, pH,cholesterol, isoprene, and/or hemoglobin) and/or other blood or bodilyfluid constituents of or relevant to a host and/or another party.

By way of example, and without limitation, monitoring system and methodembodiments described herein may include finger-stick blood sampling,blood analyte test strips, non-invasive sensors, wearable monitors (e.g.smart bracelets, smart watches, smart rings, smart necklaces orpendants, workout monitors, fitness monitors, health and/or medicalmonitors, clip-on monitors, and the like), adhesive sensors, smarttextiles and/or clothing incorporating sensors, shoe inserts and/orinsoles that include sensors, transdermal (i.e. transcutaneous) sensors,and/or swallowed, inhaled or implantable sensors.

In some embodiments, and without limitation, monitoring systems andmethods may comprise other sensors instead of or in additional to thesensors described herein, such as inertial measurement units includingaccelerometers, gyroscopes, magnetometers and/or barometers; motion,altitude, position, and/or location sensors; biometric sensors; opticalsensors including for instance optical heart rate monitors,photoplethysmogram (PPG)/pulse oximeters, fluorescence monitors, andcameras; wearable electrodes; electrocardiogram (EKG or ECG),electroencephalography (EEG), and/or electromyography (EMG) sensors;chemical sensors; flexible sensors for instance for measuring stretch,displacement, pressure, weight, or impact; galvanometric sensors,capacitive sensors, electric field sensors, temperature/thermal sensors,microphones, vibration sensors, ultrasound sensors,piezoelectric/piezoresistive sensors, and/or transducers for measuringinformation of or relevant to a host and/or another party.

What is claimed is:
 1. A sensor system for measuring an analyteconcentration, the sensor system comprising: a base having a distal sideconfigured to face towards a skin of a host; a first adhesive coupled tothe base and configured to couple the base to the skin; a transmittercoupled to the base and configured to transmit analyte measurement data;a transcutaneous analyte measurement sensor coupled to the base; andwherein the sensor is configured to be bent against the first adhesiveor the base after removal of the base from the skin.
 2. The system ofclaim 1, wherein the base further comprises a first portion and a secondportion, wherein the second portion of the base is coupled to the firstportion of the base by a hinge configured such that decreasing a pivotangle between the first and second portions of the base places a portionof the sensor between the first and second portions of the base.
 3. Thesystem of claim 2, wherein the hinge comprises a first pin rotatablycoupled to a first channel configured to retain the first pin as thefirst portion of the base rotates relative to the second portion of thebase.
 4. The system of claim 3, wherein the hinge comprises a second pinrotatably coupled to a second hole configured to retain the second pinas the first portion of the base rotates relative to the second portionof the base, wherein the first pin protrudes in a first direction, thesecond pin protrudes in a second direction, and the first direction isopposite relative to the second direction.
 5. The system of claim 2,wherein the first adhesive comprises a first section and a secondsection, the first section is coupled to the first portion of the basesuch that the first section is configured to adhere the first portion ofthe base to the skin, and the second section is coupled to the secondportion of the base such that the second section is configured to adherethe second portion of the base to the skin.
 6. The system of claim 5,wherein the hinge is configured to enable the first section of the firstadhesive to face towards the second section of the first adhesive whilethe portion of the sensor is at least partially confined between thefirst and second portions of the base.
 7. The system of claim 2, whereinthe system is configured to bend the portion of the sensor in responseto rotating the hinge, wherein the portion of the sensor is bent betweenthe first and second portions of the base to guard against a distal tipof the sensor penetrating tissue after the sensor system is removed fromthe skin.
 8. The system of claim 2, wherein the first portion of thebase is rotationally spring-loaded relative to the second portion of thebase such that the system is configured to decrease the pivot angle inresponse to a rotational spring bias.
 9. The system of claim 2, furthercomprising a torsion spring coupled to the hinge such that the torsionspring is configured to decrease the pivot angle to place the portion ofthe sensor between the first and second portions of the base.
 10. Thesystem of claim 1, further an adhesive portion configured to bend atleast a portion of the sensor towards the base, wherein a distal tip ofthe sensor is located between the base and the adhesive portion.
 11. Thesystem of claim 10, further comprising an adhesive portion configured tocollapse at least a portion of the sensor against the base.
 12. Thesystem of claim 10, further comprising a sheet that covers a distal tipof the sensor and adheres to the first adhesive such that the sheetguards against the distal tip of the sensor penetrating tissue after thesensor system is removed from the skin.
 13. The system of claim 12,wherein the sheet is configured to be pliable.
 14. The system of claim13, wherein the first adhesive couples the sheet to the base.
 15. Thesystem of claim 13, wherein the sheet comprises a first state in whichthe sheet is folded, is located proximally relative to the distal tip,does not cover the distal tip, and forms a tab configured to enable auser to unfold the sheet.
 16. The system of claim 15, wherein the sheetcomprises a second state in which the sheet is at least partiallyunfolded relative to the first state, is at least partially locateddistally relative to the distal tip, and the distal tip of the sensor isat least partially confined between the sheet and the first adhesive.17. The system of claim 12, wherein the sheet is a pliable sheet, thesystem further comprising a second sheet having a second punctureresistance that is greater than a first puncture resistance of thepliable sheet, wherein the second sheet is located between the distaltip and the pliable sheet to protect the pliable sheet from beingpunctured by the distal tip.
 18. The system of claim 17, wherein thefirst and second puncture resistances are measured using a distal tip ofthe sensor.
 19. The system of claim 17, wherein the second sheet iscoupled to the pliable sheet such that the second sheet is configured todeform the distal tip as the pliable sheet is folded over the distaltip.
 20. The system of claim 1, wherein a distal tip of the sensor is atleast partially confined between a pliable sheet and the base such thatthe pliable sheet holds at least a portion of the sensor in a bentposition and the pliable sheet is adhered to the first adhesive.
 21. Thesystem of claim 20, wherein the pliable sheet comprises a first stateand a second state, wherein in the first state, the pliable sheet islocated proximally relative to the first adhesive when the sensor systemis coupled to the skin, and wherein in the second state, the pliablesheet is located distally relative to the first adhesive when the distaltip of the sensor is at least partially confined between the pliablesheet and the base.